An Etymological Dictionary of Astronomy and Astrophysics

An → induction coil
which was a forerunner of today’s automobile ignition coil. It consists of two coils wound on a single → iron core, and uses an → alternating current produced by a break-wheel to induce a high-voltage current in the secondary coil.

See also: After Heinrich Daniel Ruhmkorff (1803-1877), a German-born instrument maker, who settled in Paris in 1819 for the rest of his life; → coil.