Cars · Electronics
Ignition Coil
The ignition coil in Honda distributor ignition.
The ignition coil is a wirewound transformer that steps the car's low battery voltage up to the tens of thousands of volts needed to jump the spark plug gap and ignite the mixture.
On most older Honda PGM-FI engines the coil lives inside the distributor, alongside the igniter and the crank and cylinder sensors. The ECU and igniter switch the coil's primary winding; the collapsing magnetic field induces a high-voltage pulse in the secondary winding, which the distributor routes to each plug in turn. Some swaps and tuning setups move to an external coil or coil-on-plug.