Ignition Coil: Description and Operation

The ignition coil, located on the left side of the engine compartment, uses the principle of mutual induction to step up low (battery) voltage to high (ignition) voltage capable of firing the spark plugs. The coil consists of two windings of wire, a primary and a secondary winding, around a laminated iron core. When current flows through the outer, primary winding, a magnetic field is created. When the primary current is interrupted by the igniter, the magnetic field collapses suddenly. The sudden change in magnetic field induces high voltage in the secondary windings. Ignition wires then direct voltage to the spark plugs. The ratio of the number of turns in the primary winding to the number of turns in the secondary winding determines voltage multiplication.