Words to Know

Alternating current (AC):Electric current in which the direction of flow changes back and forth rapidly and at a regular rate.

Armature:A part of a generator consisting of an iron core around which is wrapped a wire.

Commutator:A slip ring that serves to reverse the direction in which an electrical current flows in a generator.

Direct current (DC):Electrical current that always flows in the same direction.

Electromagnetic induction:The production of an electromotive force (something that moves electricity) in a closed electrical circuit as a result of a changing magnetic field.

Slip ring:The device in a generator that provides a connection between the armature and the external circuit.

Faraday also discovered that it makes no difference whether the coil rotates within the magnetic field or the magnetic field rotates around the coil. The important factor is that the wire and the magnetic field are in motion in relation to each other. In general, most AC generators have a stationary (fixed) magnetic field and a rotating coil, while most DC generators have a stationary coil and a rotating magnetic field.