Operation CHARM: Car repair manuals for everyone.

Ignition Coil: Description and Operation

PURPOSE
A transformer used to step up low (battery) voltage to high (ignition) voltage capable of firing the spark plugs.

LOCATION
Left side engine compartment.

OPERATION
When current flows through the outer, primary winding, a magnetic field is created. When current flow is stopped by the igniter (interrupting the ground connection), the magnetic field collapses into the iron core through the secondary windings. This sudden change in the magnetic field induces a high voltage in the secondary windings. Ignition wires then direct voltage to the spark plugs. The ratio of the number of wraps in the primary winding to the number of wraps in the secondary winding determines coil peak output voltage.

CONSTRUCTION
Consists of two windings of wire, primary and secondary, around a laminated iron core.