Fr.: bobine d'induction
A device for producing high-voltage pulses by means of → electromagnetic induction. It consists of a primary coil of a few turns of wire, wound on an iron core, and insulated from a secondary coil of many turns which surrounds it coaxially. The current in the primary, which is interrupted periodically, sets up a magnetic field, first big, then zero. This changing field induces a large voltage in the secondary.