Optical Distributor Ignition System
An optical crank angle sensor mounted inside of distributor monitors engine speed and piston location. See Fig 1 . See CRANK ANGLE SENSOR under INPUT DEVICES heading in this article. Signals created by the crank angle sensor are sent to the Electronic Control Unit (ECU). The ECU then delivers ignition timing signals to the power transistor. Power transistor triggers ignition coil. Power for ignition coil is supplied by the ignition switch when in the START or RUN position.