The first is the type of ignition coil. There are two main types: coil-on-plug and coil pack. Coil-on-plug ignition systems have a separate ignition coil for each spark plug, while coil pack ...

the ignition system consists of an ignition coil, which converts battery voltage to higher voltage, and the spark plug wires that join these components. Advancements have greatly reduced the need ...

This type of ignition system with a separate ignition coil -- a rotor in a distributor that sends electrical current to each spark plug through wires in the cap -- began to phase out in the 1970s.