Ignition Control Module: Description and Operation

Power Transistor:

PURPOSE
The power transistor is a voltage amplifier that allows the signal sent from the Engine Control Module (ECM) to activate the primary circuit in the ignition coil.

OPERATION
It allows the signal sent from the ECM (very low current) to activate the primary circuit in the ignition coil (much higher current). This induces high voltage in the secondary windings of the ignition coil, providing spark to the distributor cap and plugs.