Induction coil
An induction coil (archaicly known as a Ruhmkorff coil) is a type of disruptive discharge coil. These coils are passive electrical device used to produce high voltage pulses from a low voltage DC supply.
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Description
Induction coils consist of two coils of copper wire wound around an iron core. One coil is made of coarse wire, the other of many turns of fine wire. Electrical current is passed through the first coil, creating a magnetic field which stores energy. When the current is interrupted the magnetic field collapses, releasing the energy from the second coil as a high voltage spike. The term "Induction coil" is also used for a coil carrying high-frequency AC current and intended to induce some effect such as in induction heating or zone melting.
History
The induction coil was discovered in early experiments with electricity, probably by Nicholas Callan in 1836, and further developed by Heinrich Ruhmkorff. This type of disruptive discharge coil remains in common use as the "ignition coil" or "spark coil" in the ignition system of the internal combustion engine. A small version is used to trigger the flash tube of a camera.
See also
Further reading
- Norrie, H. S., "Induction Coil : How to make, use, and repair them". Norman H. Schneider, 1907, New York. 4th edition.