Find the correct Ignition Coils for your car
Ignition coils are sometimes referred to as spark coils, and are designed to provide the voltage that's needed to get an internal combustion engine going.
Your car battery will have a relatively low voltage, whilst the spark plugs require a large voltage in order to spark properly. The ignition coil is designed to increase the voltage from 12 volts up to the level required for ignition (about 400 volts).
It's fair to say, then, that ignition coils are pretty vital to the running of your car's engine.