Basic ignition coil principles - functional principle: Transformation

The fundamental principle is the same for all ignition coils: A voltage in the high kilovolt range - up to 45,000 volts in modern vehicles - must be generated from a low battery voltage of 12 volts. Therefore, the voltage is transformed and multiplied.

The principles described here also pertain to traditional cylinder ignition coils and modern block ignition coils or pencil coils.