MITSUBISHI Electronic Ignition: Operation

Whenever the ignition switch is "ON", the primary circuit of the ignition coil is energized. As the distributor shaft rotates, the armature (reluctor) rotates inside the magnetic pick-up coil (stator) assembly.

As the teeth of the armature pass the pegs of the pick-up coil, a signal is sent to the control module (ignitor). The module then breaks the primary circuit in the coil. This causes a high voltage surge in the coil secondary circuit, firing the spark plugs.