Pick-Up Coil: Description and Operation

Crankshaft Position Sensor Showing Signal Rotor Alignment:

The signal generator, located in the distributor, consists of a signal rotor and pick-up coil. The signal rotor (also referred to as a reluctor) turns with the camshaft driven distributor shaft. The pick-up coil is attached to the distributor breaker plate. As each tooth of the reluctor passes the pick-up coil, it disturbs magnetic flux lines around the coil, generating a voltage pulse. This pulse is the signal utilized by the igniter power transistor to time its interruption of current flow to the ignition coil primary circuit. Each time current flow through the primary circuit is stopped, high coil secondary voltage is produced and directed to the appropriate spark plug.