1. A small rotating cap-like unit at the end of the distributor shaft. It is located on the breaker cam inside the cap. It connects between the center electrode and the various outer spark plug terminals as it turns, thus distributing the high voltage from the ignition coil secondary winding to the proper spark plug .
2. A rotating armature inside a stator . As the rotor turns within the stator, electricity is produced to power the electrical components .
3. A trichoidal device in a rotary engine.