Physics Book - User contributions [en]

Charging and Discharging a Capacitor

2016-11-26T01:05:14Z

Parya6: /* External links */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

'''Time Constant'''

The time constant of a circuit, with units of time, is the product of R and C. The time constant is the amount of time required for the charge on a charging capacitor to rise to 63% of its final value. The following are equations that result in a rough measure of how long it takes charge or current to reach equilibrium.

Q = (C*emf)[1−e^(−t/RC)]

I = (emf/R)[e^(−t/RC)]

===The Effect of Surface Area===

[[File:Cap1vscap2.png]]

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

[[File:Fringe_field_eq.png]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]
#WebAssign "Lab 4 - Charge and Discharge of a Capacitor"[http://www.webassign.net/labsgraceperiod/ncsulcpem2/lab_4/manual.html]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T01:03:46Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

'''Time Constant'''

The time constant of a circuit, with units of time, is the product of R and C. The time constant is the amount of time required for the charge on a charging capacitor to rise to 63% of its final value. The following are equations that result in a rough measure of how long it takes charge or current to reach equilibrium.

Q = (C*emf)[1−e^(−t/RC)]

I = (emf/R)[e^(−t/RC)]

===The Effect of Surface Area===

[[File:Cap1vscap2.png]]

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

[[File:Fringe_field_eq.png]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T01:00:36Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

'''Time Constant'''
The time constant of a circuit, with units of time, is the product of R and C. The time constant is the amount of time required for the charge on a charging capacitor to rise to 63% of its final value.

===The Effect of Surface Area===

[[File:Cap1vscap2.png]]

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

[[File:Fringe_field_eq.png]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:56:35Z

Parya6: /* The Effect of Surface Area */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

===The Effect of Surface Area===

[[File:Cap1vscap2.png]]

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

[[File:Fringe_field_eq.png]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Cap1vscap2.png

2016-11-26T00:55:38Z

Parya6:

Charging and Discharging a Capacitor

2016-11-26T00:52:14Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

===The Effect of Surface Area===

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

[[File:Fringe_field_eq.png]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Fringe field eq.png

2016-11-26T00:51:04Z

Parya6:

Charging and Discharging a Capacitor

2016-11-26T00:50:40Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

===The Effect of Surface Area===

For two different circuits, each with one of the above capacitors, the circuit with the second capacitor (with more surface area) has a current that stays more constant than the first. The larger capacitor also ends up with a greater amount of charge on its plates.

This is because fringe field magnitude is inversely proportional to plate area, as shown in the equation below. In the first, short time interval, roughly equal quantities of charge will accumulate on the capacitor plates. However, due to its greater area, capacitor 2 will have a weaker fringe field. This, in turn, results in a greater net field for that circuit. This greater net field results in more charge for that circuit compared to the other. More charge will be driven from the negative to the positive plate, and the drift speed changes less for capacitor 2 than capacitor 1.

The equation for fringe electric field is the following:

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:36:27Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their equilibrium or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attractions to the opposite charge) or moving towards the plate of opposite charge. While charging, until the electron current stops running at equilibrium, the charge on the plates will continue to increase until the point of equilibrium, at which point it levels off. Conversely, while discharging, the charge on the plates will continue to decrease until a charge of zero is reached.

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:31:32Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their maximum charge or zero, respectively, the current slows down to eventually become zero as well.

When the plates are charging or discharging, charge is either accumulating on either sides of the plates (against their natural attracti

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:30:20Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

When the capacitor begins to charge or discharge, current runs through the circuit. It follows logic that whether or not the capacitor is charging or discharging, when the plates begin to reach their maximum charge or zero, respectively, the current slows down to eventually become zero as well.

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:28:05Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs2.png]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Priyaaryacapacitorgraphs2.png

2016-11-26T00:27:40Z

Parya6:

Charging and Discharging a Capacitor

2016-11-26T00:26:55Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs.jpg]]

[[File:Priyaaryacapacitorgraphs2.png]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:25:45Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs.jpg]]

[[File:Priyaaryacapacitorgraphs2.jpg]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-26T00:10:34Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Priyaaryacapacitorgraphs.jpg]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Priyaaryacapacitorgraphs.jpg

2016-11-26T00:09:57Z

Parya6: Parya6 uploaded a new version of "File:Priyaaryacapacitorgraphs.jpg"

Charging and Discharging a Capacitor

2016-11-25T23:49:08Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Priyaaryacapacitorgraphs.jpg

2016-11-25T23:33:37Z

Parya6:

File:Capacitorgraphs.jpg

2016-11-25T23:31:50Z

Parya6: Parya6 uploaded a new version of "File:Capacitorgraphs.jpg"

File:Capacitorgraphs.jpg

2016-11-25T23:29:13Z

Parya6:

File:Capacitooooooors.jpg

2016-11-25T23:25:25Z

Parya6:

File:Capacitorsgraphschardischar.jpg

2016-11-25T23:23:56Z

Parya6:

Charging and Discharging a Capacitor

2016-11-25T23:07:12Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:capacitorgraphs.jpg]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T23:02:21Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T23:01:28Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Capacitor Graphs.png]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T22:57:34Z

Parya6: /* Current and Charge within the Capacitors */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Capacitor Graphs.jpg]]

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

File:Capacitor Charge and Discharge Graph.JPG

2016-11-25T22:54:28Z

Parya6:

Charging and Discharging a Capacitor

2016-11-25T22:52:48Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

===The Effect of Surface Area===

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T22:29:55Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T22:29:16Z

Parya6: /* The Main Idea */

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

===Current and Charge within the Capacitors===

The following graphs depict how current and charge within charging and discharging capacitors change over time.

[[File:Capacitor Charging.svg|Capacitor Charging]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T22:24:14Z

Parya6:

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)

'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Charging and Discharging a Capacitor

2016-11-25T22:23:59Z

Parya6:

The main purpose of having a capacitor in a circuit is to store electric charge. For intro physics you can almost think of them as a battery.

CLAIMED BY SAMAH HISAMUDDIN (Spring 2016)
'''Edited by Priya Arya (Fall 2016)'''

==The Main Idea==

'''Discharging a Capacitor'''

[[File:Discharging a capacitor wiki.PNG]]

A circuit with a charged capacitor has an electric fringe field inside the wire. This field creates an electron current. The electron current will move opposite the direction of the electric field. However, so long as the electron current is running, the capacitor is being discharged. The electron current is moving negative charges away from the negatively charged plate and towards the positively charged plate. Once the charges even out or are neutralized the electric field will cease to exist. Therefore the current stops running.

In the example where the charged capacitor is connected to a light bulb you can see the electric field is large in the beginning but decreases over time. The electron current is also greater in the beginning and decreases over time. Because of this the light bulb starts out shining brightly but slowly dims and goes out.

'''Charging a Capacitor'''

[[File:Charging a capacitor wiki.PNG]]

Charging a capacitor isn’t much more difficult than discharging and the same principles still apply. The circuit consists of two batteries, a light bulb, and a capacitor. Essentially, the electron current from the batteries will continue to run until the circuit reaches equilibrium (the capacitor is “full”). Just like when discharging, the bulb starts out bright while the electron current is running, but it slowly dims and goes out as the capacitor charges.

The electron current will flow out the negative end of the battery as usual (conventional current will exit the positive end). Positive charges begin to build up on the right plate and negative charges on the left. The electric field slowly decreases until the net electric field is 0. The fringe field is equal and opposite to the electric field caused by everything else.

If you were to draw a box around the capacitor and label it with positive and negative ends it would look like a battery. It also behaves like a battery. The electron current will continue to flow and the electric field will continue to exist until the potential difference across the capacitor is equal to that of the batteries (sum of emf of all batteries in the circuit).

'''Resistors'''

The amount of resistance in the circuit will determine how long it takes a capacitor to charge or discharge. The less resistance (a light bulb with a thicker filament) the faster the capacitor will charge or discharge. The more resistance (a light bulb with a thin filament) the longer it will take the capacitor to charge or discharge. The thicker filament bulb will be brighter, but won't last as long as a thin filament bulb. '''V = IR''', The larger the resistance the smaller the current.

===A Mathematical Model===

'''V = IR'''

'''E = (Q/A)/ε0'''

'''C = Q/V = ε0A/s'''

'''V = (Q/A)s/ε0'''

===A Computational Model===

[[File:Capacitor Charging.svg|Capacitor Charging]]

==Examples==

'''Question 1'''

Doubling the radius of the capacitor

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the radius of the capacitor

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

Doubling the distance between the plates

A) quarters the capacitance

B) halves the capacitance

C) doubles the capacitance

D) quadruples the capacitance

Doubling the capacitance

A) quarters the electric field between the plates

B) halves the electric field between the plates

C) doubles the electric field between the plates

D) quadruples the electric field between the plates

ANS: D, B, A, C

'''Question 2'''

[[File:Circuits problem 1 wiki.PNG]]

What is the current at points A,B, and C when the capacitor is not yet charged and when the capacitor is fully charged?

When the capacitor is fully charged what is the charge on the plates?

'''Answer:'''

[[File:Circuits problem 1 wiki answers.PNG]]

'''Question 3'''

[[File:Circuits problem 2 wiki.PNG]]

The switch has been closed for a long time.

What is the current at each point?

What is the charge on the capacitor?

Is the light bulb lit?

The switch is opened.

Immediately after the switch is opened is the bulb lit? After a while?

What current is initially running through the bulb?

Which direction is the current moving?

'''Answer:'''

[[File:Circuits problem 2 wiki answers.PNG]]

==Connectedness==

Capacitor can be temporary batteries. Capacitors in parallel can continue to supply current to the circuit if the battery runs out. This is interesting because the capacitor gets its charge from being connected to a chemical battery, but the capacitor itself supplies voltage without chemicals.

Capacitors are being researched for applications in electromagnetic armour and electromagnetic weapons. Currently capacitors are used as detonators in nuclear weapons. Capacitors also are largely involved in separations of AC and DC components.

==History==

Put this idea in historical context. Give the reader the Who, What, When, Where, and Why.
In 1745 Ewald Georg von Kleist was the first to "discover" capacitors in Germany. He connected a generator to glass jars of water and charged them. When he touched the wire they were connected to he shocked himself (discharged the capacitor). At the same time Pieter van Musschenbroek made a similar capacitor and named it the Leyden Jar. When Benjamin Franklin studied the Leyden Jar he determined, among other things, that the charge was stored on the glass. During his studies Franklin was the first to give the capacitor the name battery. Since then batteries have most often been electro-chemical cells of capacitors made of sheets of conducting and dielectric material.

== See also ==
===Further reading===
#Williams, Henry Smith. "A History of Science Volume II, Part VI: The Leyden Jar Discovered"
#Keithley, Joseph F. (1999). The Story of Electrical and Magnetic Measurements: From 500 BC to the 1940s

===External links===

#Wikipedia Page "Capacitor"[https://en.wikipedia.org/wiki/Capacitor]
#Khan Academy[https://www.khanacademy.org/science/physics/circuits-topic]

==References==

#Chabay, Ruth W., and Bruce A. Sherwood. Matter and Interactions. 3rd ed. Vol. 2. N.p.: John Wiley and Sons, 2002. Print.
#"Capacitor." Wikipedia. Wikimedia Foundation, n.d. Web. 05 Dec. 2015.

[[Category:Which Category did you place this in?]]

Meissner effect

2016-11-25T21:58:56Z

Parya6:

==What is the Meissner Effect==

The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. Below the transition temperature, superconductors cancel nearly all interior magnetic fields actively. The effect that occurs, leading to a zero net magnetic effect in the material, can be attributed to diamagnetism.

[[File:Meissner effect1.png|200px|thumb|right|alt text]]

===What is diamagnetism?===
Some materials tend to expel a magnetic field, materials that do this are called diamagnetic, but the effects of this diamagnetism are weak. For example, water and the human body are diamagnetic materials. Diamagnetism is a weak repulsion from a magnetic field. It is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It results from changes in the orbital motion of electrons. Applying a magnetic field creates a magnetic force on a moving electron in the form of F = Qv × B. This force changes the centripetal force on the electron, causing it to either speed up or slow down in its orbital motion. This changed electron speed modifies the magnetic moment of the orbital in a direction opposing the external field.

In superconducting material the Meissner effect creates currents which completely oppose the magnetic field applied by a magnet, in other words they will repel a magnet causing it to levitate. This consequently makes a superconductor in the Meissner state a perfect diamagnet.

==How does it Work?==

A super conductor with little or no magnetic field within it is said to be in the Meissner state and breaks down when the magnetic field is too large.
A superconductor is fundamentally different from a conductor, because Faraday’s law of induction alone does not explain magnetic repulsion by a superconductor. At a temperature below its Critical Temperature, Tc, a superconductor will not allow any magnetic field to freely enter it. This is because microscopic magnetic dipoles are induced in the superconductor that oppose the applied field. This induced field then repels the source of the applied field, and will consequently repel the magnet associated with that field. [[File:Floating magnet.png|200px|thumb|right|alt text]]This implies that if a magnet was placed on top of the superconductor when the superconductor was above its Critical Temperature, and then it was cooled down to below Tc, the superconductor would then exclude the magnetic field of the magnet. This means that a magnet already levitating above a superconductor does not demonstrate the Meissner effect, while a magnet that is initially stationary and then repelled by a superconductor as it is cooled through its critical temperature does.

===A Mathematical Model===

===A Computational Model===

==Examples==

===Simple===

===Medium===

===Difficult===

==What did it lead to?==
The theory of the Meissner effect led to the phenomenological theory of superconductivity by Frits London and Heinz London in 1935. This theory explained resistance less transport and the Meissner effect, and allowed the first theoretical predictions for superconductivity to be made as seen below.

[[File:London Equations.png]]

By using the London equations and Maxwell equations, one can predict how the magnetic field and surface current vary with distance from the surface of a superconductor.

==Connectedness==

===Further reading===
Albert Einstein (1922). "Theoretical remark on the superconductivity of metals". arXiv:physics/0510251v2. Bibcode:2005physics..10251E.
Fritz Wolfgang London (1950). "Macroscopic Theory of Superconductivity". Superfluids. Structure of matter series 1. OCLC 257588418.. Revised 2nd edition, Dover (1960) ISBN 978-0-486-60044-4. By the man who explained the Meissner effect. pp. 34–37 gives a technical discussion of the Meissner effect for a superconducting sphere.

===External links===
Vidoes to aid in the understanding of the concept.

https://www.youtube.com/watch?v=44mVZdnR6Yc

https://www.youtube.com/watch?v=bnyB-PInFA4

==References==
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/meis.html
http://www.supraconductivite.fr/en/index.php?p=supra-levitation-meissner-more
http://lrrpublic.cli.det.nsw.edu.au/lrrSecure/Sites/Web/physics_explorer/physics/lo/superc_12/superc_12_02.htm
http://www.chm.bris.ac.uk/webprojects2006/Truscott/paged_r.html
http://www.imagesco.com/articles/superconductors/superconductor-meissner-efsfect.html

See link to the right to read more on superconductors.
[[http://www.physicsbook.gatech.edu/Superconductors]]

Meissner effect

2016-11-25T21:58:33Z

Parya6: /* How does it Work? */

'''Edited by Priya Arya - Fall 2016'''
==What is the Meissner Effect==

The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. Below the transition temperature, superconductors cancel nearly all interior magnetic fields actively. The effect that occurs, leading to a zero net magnetic effect in the material, can be attributed to diamagnetism.

[[File:Meissner effect1.png|200px|thumb|right|alt text]]

===What is diamagnetism?===
Some materials tend to expel a magnetic field, materials that do this are called diamagnetic, but the effects of this diamagnetism are weak. For example, water and the human body are diamagnetic materials. Diamagnetism is a weak repulsion from a magnetic field. It is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It results from changes in the orbital motion of electrons. Applying a magnetic field creates a magnetic force on a moving electron in the form of F = Qv × B. This force changes the centripetal force on the electron, causing it to either speed up or slow down in its orbital motion. This changed electron speed modifies the magnetic moment of the orbital in a direction opposing the external field.

In superconducting material the Meissner effect creates currents which completely oppose the magnetic field applied by a magnet, in other words they will repel a magnet causing it to levitate. This consequently makes a superconductor in the Meissner state a perfect diamagnet.

==How does it Work?==

A super conductor with little or no magnetic field within it is said to be in the Meissner state and breaks down when the magnetic field is too large.
A superconductor is fundamentally different from a conductor, because Faraday’s law of induction alone does not explain magnetic repulsion by a superconductor. At a temperature below its Critical Temperature, Tc, a superconductor will not allow any magnetic field to freely enter it. This is because microscopic magnetic dipoles are induced in the superconductor that oppose the applied field. This induced field then repels the source of the applied field, and will consequently repel the magnet associated with that field. [[File:Floating magnet.png|200px|thumb|right|alt text]]This implies that if a magnet was placed on top of the superconductor when the superconductor was above its Critical Temperature, and then it was cooled down to below Tc, the superconductor would then exclude the magnetic field of the magnet. This means that a magnet already levitating above a superconductor does not demonstrate the Meissner effect, while a magnet that is initially stationary and then repelled by a superconductor as it is cooled through its critical temperature does.

===A Mathematical Model===

===A Computational Model===

==Examples==

===Simple===

===Medium===

===Difficult===

==What did it lead to?==
The theory of the Meissner effect led to the phenomenological theory of superconductivity by Frits London and Heinz London in 1935. This theory explained resistance less transport and the Meissner effect, and allowed the first theoretical predictions for superconductivity to be made as seen below.

[[File:London Equations.png]]

By using the London equations and Maxwell equations, one can predict how the magnetic field and surface current vary with distance from the surface of a superconductor.

==Connectedness==

===Further reading===
Albert Einstein (1922). "Theoretical remark on the superconductivity of metals". arXiv:physics/0510251v2. Bibcode:2005physics..10251E.
Fritz Wolfgang London (1950). "Macroscopic Theory of Superconductivity". Superfluids. Structure of matter series 1. OCLC 257588418.. Revised 2nd edition, Dover (1960) ISBN 978-0-486-60044-4. By the man who explained the Meissner effect. pp. 34–37 gives a technical discussion of the Meissner effect for a superconducting sphere.

===External links===
Vidoes to aid in the understanding of the concept.

https://www.youtube.com/watch?v=44mVZdnR6Yc

https://www.youtube.com/watch?v=bnyB-PInFA4

==References==
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/meis.html
http://www.supraconductivite.fr/en/index.php?p=supra-levitation-meissner-more
http://lrrpublic.cli.det.nsw.edu.au/lrrSecure/Sites/Web/physics_explorer/physics/lo/superc_12/superc_12_02.htm
http://www.chm.bris.ac.uk/webprojects2006/Truscott/paged_r.html
http://www.imagesco.com/articles/superconductors/superconductor-meissner-efsfect.html

See link to the right to read more on superconductors.
[[http://www.physicsbook.gatech.edu/Superconductors]]

Meissner effect

2016-11-25T21:55:34Z

Parya6:

'''Edited by Priya Arya - Fall 2016'''
==What is the Meissner Effect==

The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. Below the transition temperature, superconductors cancel nearly all interior magnetic fields actively. The effect that occurs, leading to a zero net magnetic effect in the material, can be attributed to diamagnetism.

[[File:Meissner effect1.png|200px|thumb|right|alt text]]

===What is diamagnetism?===
Some materials tend to expel a magnetic field, materials that do this are called diamagnetic, but the effects of this diamagnetism are weak. For example, water and the human body are diamagnetic materials. Diamagnetism is a weak repulsion from a magnetic field. It is a form of magnetism that is only exhibited by a substance in the presence of an externally applied magnetic field. It results from changes in the orbital motion of electrons. Applying a magnetic field creates a magnetic force on a moving electron in the form of F = Qv × B. This force changes the centripetal force on the electron, causing it to either speed up or slow down in its orbital motion. This changed electron speed modifies the magnetic moment of the orbital in a direction opposing the external field.

In superconducting material the Meissner effect creates currents which completely oppose the magnetic field applied by a magnet, in other words they will repel a magnet causing it to levitate. This consequently makes a superconductor in the Meissner state a perfect diamagnet.

==How does it Work?==

A super conductor with little or no magnetic field within it is said to be in the Meissner state and breaks down when the magnetic field is too large
A superconductor is fundamentally different from a conductor, because Faraday’s law of induction alone does not explain magnetic repulsion by a superconductor. At a temperature below its Critical Temperature, Tc, a superconductor will not allow any magnetic field to freely enter it. This is because microscopic magnetic dipoles are induced in the superconductor that oppose the applied field. This induced field then repels the source of the applied field, and will consequently repel the magnet associated with that field. [[File:Floating magnet.png|200px|thumb|right|alt text]]This implies that if a magnet was placed on top of the superconductor when the superconductor was above its Critical Temperature, and then it was cooled down to below Tc, the superconductor would then exclude the magnetic field of the magnet. This means that a magnet already levitating above a superconductor does not demonstrate the Meissner effect, while a magnet that is initially stationary and then repelled by a superconductor as it is cooled through its critical temperature does.

===A Mathematical Model===

===A Computational Model===

==Examples==

===Simple===

===Medium===

===Difficult===

==What did it lead to?==
The theory of the Meissner effect led to the phenomenological theory of superconductivity by Frits London and Heinz London in 1935. This theory explained resistance less transport and the Meissner effect, and allowed the first theoretical predictions for superconductivity to be made as seen below.

[[File:London Equations.png]]

By using the London equations and Maxwell equations, one can predict how the magnetic field and surface current vary with distance from the surface of a superconductor.

==Connectedness==

===Further reading===
Albert Einstein (1922). "Theoretical remark on the superconductivity of metals". arXiv:physics/0510251v2. Bibcode:2005physics..10251E.
Fritz Wolfgang London (1950). "Macroscopic Theory of Superconductivity". Superfluids. Structure of matter series 1. OCLC 257588418.. Revised 2nd edition, Dover (1960) ISBN 978-0-486-60044-4. By the man who explained the Meissner effect. pp. 34–37 gives a technical discussion of the Meissner effect for a superconducting sphere.

===External links===
Vidoes to aid in the understanding of the concept.

https://www.youtube.com/watch?v=44mVZdnR6Yc

https://www.youtube.com/watch?v=bnyB-PInFA4

==References==
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/meis.html
http://www.supraconductivite.fr/en/index.php?p=supra-levitation-meissner-more
http://lrrpublic.cli.det.nsw.edu.au/lrrSecure/Sites/Web/physics_explorer/physics/lo/superc_12/superc_12_02.htm
http://www.chm.bris.ac.uk/webprojects2006/Truscott/paged_r.html
http://www.imagesco.com/articles/superconductors/superconductor-meissner-efsfect.html

See link to the right to read more on superconductors.
[[http://www.physicsbook.gatech.edu/Superconductors]]