Description: The prongs at the end of the pivoted arm dip into mercury filled recesses. This completes a circuit which energises a coil around the iron pivot arm and functions as an electromagnet. The magnetic polarity is so arranged that a permanent magnet underneath the arm then repels the pivot arm and causes the circuit to break, but the prongs at the other end of the pivot arm then close an identical circuit at that end and the procedure repeats endlessly. The output of the interrupter is fed to an induction coil which greatly increases the voltage applied to the patient by transformer action.[1]
An interrupter in electrical engineering is a device used to interrupt the flow of a steady direct current for the purpose of converting a steady current into a changing one. Frequently, the interrupter is used in conjunction with an inductor (coil of wire) to produce increased voltages either by a back emf effect or through transformer action. The largest industrial use of the interrupter was in the induction coil, the first transformer, which was used to produce high voltage pulses in scientific experiments and to power arc lamps, spark gap radio transmitters, and the first X-ray tubes, around the turn of the 20th century. Its largest use was the contact breaker or "points" in the distributor of the ignition system of gasoline engines, which served to periodically interrupt the current to the ignition coil producing high voltage pulses which create sparks in the spark plugs. It is still used in this application.