Ignition coil: where does the high voltage come from

Useful to know

The ignition coil provides the high voltage required for the spark of the candle. Bosch describes a primary and secondary electrical circuit: the power outage in the primary creates a high-voltage pulse in the secondary. The candle is where the spark forms. [1]

There are various constructions, including separate coils to the candles and solutions serving several candles. Therefore, a picture of a single motor is not a universal scheme for all gasoline cars.

In case of ignition gaps, the coil is only one of the possible parts to check. The symptom and code should be associated with real measurements and procedure for the particular engine. It is not appropriate to check a spark by randomly disconnecting and holding high-voltage parts. For the reader, the essential is the distinction: the coil creates the necessary electrical impulse, and the candle uses it for ignition.