Induction coil

Induction coil
Induction coil
	Antique induction coil used in schools, from around 1900, Bremerhaven, Germany
Classification	Transformer
Industry	Electric power
Application	High voltage
Inventor	Nicholas Callan
Invented	1836

An induction coil or "spark coil" (archaically known as an inductorium or Ruhmkorff coil^[1] after Heinrich Rühmkorff) is a type of electrical transformer^[2]^[3]^[4] used to produce high-voltage pulses from a low-voltage direct current (DC) supply.^[1]^[5] To create the flux changes necessary to induce voltage in the secondary coil, the direct current in the primary coil is repeatedly interrupted by a vibrating mechanical contact called an interrupter.^[1] Invented in 1836 by the Irish-Catholic priest Nicholas Callan, with additional research by Charles Grafton Page and others,^[1] the induction coil was the first type of transformer. It was widely used in x-ray machines,^[1]^[6] spark-gap radio transmitters,^[1]^[6] arc lighting and quack medical electrotherapy devices from the 1880s to the 1920s. Today its only common use is as the ignition coils in internal combustion engines and in physics education to demonstrate induction.

^ ^a ^b ^c ^d ^e ^f Fleming, John Ambrose (1911). "Induction Coil" . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 14 (11th ed.). Cambridge University Press. pp. 502–505.
^ "Annus Mirabilis". The New Scientist. 5 (19). London: Reed Business Information: 445. February 1959. Retrieved 20 November 2018.
^ Strickland, Jeffrey (2011). Weird Scientists: the Creators of Quantum Physics. Lulu. p. 98. ISBN 978-1-257-97624-9.
^ Waygood, Adrian (2016). Electrical Science for Technicians. Routledge. p. 162. ISBN 978-1-317-53491-4.
^ Collins, Archie F. (1908). The Design and Construction of Induction Coils. New York: Munn & Co. p. 98. p.98
^ ^a ^b Collins, 1908, p. iii