Tesla coil

claimed by Julia Denniss

Tesla coil

Named for its inventor, Nikola Tesla, a Tesla coil is an electrical resonant transformer circuit capable of producing a potential of millions of volts. 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". Tesla coils were used in experiments in electrical lighting, wireless telegraphy, and X-rays. The Tesla coil first appeared in Tesla's patent No. 454,622 (1891) for use in electric lighting. Tesla coils can output anywhere from 50 kilovolts to several million volts for larger coils. The alternating current output is usually between 50 kHz and 1 MHz, in the low frequency radio range.

History

Around 1891, Tesla created the Tesla coil while expanding on and repeating the experiments of Heinrich Hertz, who had discovered electromagnetic radiation in 1888. As part of the design, Tesla initially utilized a high-speed alternator but found that the high frequency current melted the insulation and overheated the iron core. He then included a "sparkgap" into the system, which put a gap of insulating material between the primary and secondary windings. He also placed a capacitor between the alternator and the primary winding to avoid burning out the coil.

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

[1]

External links

[2]

References

http://onetesla.com/about

http://scipp.ucsc.edu/edu/tesla/teslacoil/whatisateslacoil.html

http://www.richieburnett.co.uk/operation.html#operation

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.

Mazzotto, Domenico (1906). Wireless telegraphy and telephony. Whittaker and Co. p. 146.

W. Bernard Carlson, Tesla: Inventor of the Electrical Age, Princeton University Press - 2013, page 120