Tesla coil
claimed by Julia Denniss
Tesla coil
Named for its inventor, Nikola Tesla, Tesla coils are "fantastic high voltage long sparking displays" that can millions of volts of electricity. These contraptions can produce millions of volts from much smaller voltages. The coil is used to produce high-voltage, low-current, high frequency alternating-current electricity. The Tesla coil was initially created as a power supply for Tesla's "System of Electric Lighting".
History
Around 1891, the invention's namesake began experimenting with devices that could create different change and influence electricity. Tesla's main intention for creating this device was to test the theory of electromagnetism proposed by Heinrich Hertz. By putting together various capacitors and alternators (along with other parts in different iterations), Tesla was able to create the recognizable coil with the ball on top that we see today.
Fundamental Principles
Tesla coils can produce massive electric fields due to the ability to create high voltages. It is comparable to a transformer, yet there are key differences between the two.
While a regular transformer relies on the turns of a coil, Tesla's devices are more affected by the "resonance" instead. A major part of this "resonance" effect is through the spark plug gap (in most variations). With a significant amount of voltage, the internal spark plug gap will become ionized air, becoming a sort of circuit.
Through a series of capacitors, the coil can produce the millions of volts that are popularly seen.
The equation to find the voltage is
V2 = V1\sqrt{C1 \ C2} = V1\sqrt{L2 \ L1}
where V is the voltage, C is the capacitance, and L is the inductance.
Usage
Until the 1920s, Tesla coils were used commercially as sparkgap radio transmitters for wireless telegraphy. Guglielmo Marconi eventually replaced Tesla's sparkgap with less expensive technology involving a metal powder coherer on the receiver side. The Tesla coil was also used in electrotherapy and other pseudomedical devices. Today, Tesla coils are mainly used in entertainment, educational displays, music, and (with some small coils) in leak detection in high vacuum systems. A hobby community of "coilers" has been built by those who build and design Tesla coils for personal use. Tesla coils can be used to produce music by modulating the system's "break rate", or the rate and duration of high power radio frequency bursts. These can be regulated with a control unit and MIDI music data to produce the effect of a "singing" coil. In high vacuum systems, it is imperative to ensure that there are no leaks, as even tiny ones could affect the system. Scientists test for the presence of leaks by using high-voltage discharges given off by a small Tesla coil. The high voltage electrode of the coil is placed over the outside surface of the apparatus being tested when it is evacuated. The discharge given off by the coil travels through any leak below it and illuminates the imperfection to indicate points that must be filled in before using the apparatus. Glassware is often tested in this way.
Future
Due to the large amounts of voltages that they can create, Tesla coils could potentially provide wireless transmission of power. This would allow the transition away from cables and instead to a more mobile form of electrical power. However, the technology is still difficult to implement due to cost and distance limitations. With more advancements in technology, this idea could potentially become reality.
See also
http://www.physicsbook.gatech.edu/Nikola_Tesla
Further reading
External links
References
http://scipp.ucsc.edu/edu/tesla/teslacoil/whatisateslacoil.html
http://www.richieburnett.co.uk/operation.html#operation
https://en.wikipedia.org/wiki/Tesla_coil
Dommermuth-Costa, Carol (1994). Nikola Tesla: A Spark of Genius. Twenty-First Century Books. p. 75. ISBN 0-8225-4920-4.
U.S. Patent No. 454,622, Nikola Tesla, SYSTEM OF ELECTRIC LIGHTING, filed 23 June 1891; granted 25 April 1891
Duckon 2007-Steve Ward's Singing Tesla Coil video Archived January 1, 1970, at the Wayback Machine.