HITACHI Electronic Ignition System - SUBARU: Description
The Hitachi electronic distributor consists of a housing, rotor and distributor cap. See Fig 1. A reluctor, mounted on the shaft and governor assembly, combines with the pick-up coil to replace the conventional cam and breaker points. With the ignition switch "ON", the distributor reluctor rotates past the pick-up coil/control unit. As each tooth of the reluctor approaches and passes the pick-up coil/control unit, a signal is sent to the control unit. The control unit then turns the primary circuit in the ignition coil on and off as each tooth passes the pick-up coil. This causes a build-up and collapse of a magnetic field in the coil, resulting in a high voltage surge in the coil's secondary circuit. This fires the spark plugs. See Figure.