MagnetsMake the magnetic field. Two poles, one above and one below the coil. Big generators use electromagnets, called field coils, instead.
CoilLoops of wire that turn in the magnetic field. That makes a current flow in them. Also called the armature.
TurbineBlades on the shaft pushed round by steam, falling water or wind. It supplies the turning.
Slip ringsTwo metal rings on the shaft that turn with it. One is joined to each end of the coil.
Light bulbThe light bulb, standing for the load: anything the generator powers.
Other 3
ShaftThe rod that the coil is fixed to and turns with.
BrushesBlocks, usually carbon, that press on the turning slip rings. They carry the current out.
External circuitWires that carry the current from the brushes to whatever it powers.
How this list was compiled: Read 2026-09-27. (1) OpenStax, College Physics 2e, section 23.5 Electric Generators, https://openstax.org/books/college-physics-2e/pages/23-5-electric-generators : generators induce an emf by rotating a coil in a magnetic field; the more turns, the larger their area and the stronger the field, the greater the output voltage; the emf is sent to a light bulb through a system of rings and brushes; split rings, called commutators, give pulsed DC; the mechanical energy that turns the coil can come from falling water, steam or wind, and in a steam turbine the steam moves over blades on the shaft. (2) Wikipedia, Electric generator, https://en.wikipedia.org/wiki/Electric_generator : a rotor turns inside a stator; the field comes from permanent magnets or field coils; the armature windings generate the current; a dynamo uses a commutator; the prime mover turns the generator shaft. Licence: own work
The drawing: Drawn for this site by script, 2026-09-27. Own work, nothing traced. Licence: own work
How it works
These are the parts of a generator on the simple AC generator of a physics class: a coil turning between magnets, with the current taken out to a light bulb. Start with the 5 main parts.
Read the full guide
Making the current
The turbine turns the shaft, and the coil on the shaft spins between the magnets. As it turns in the magnetic field, a current flows in the coil. More turns of wire, a bigger coil or stronger magnets give a higher voltage.
Getting it out
Each end of the coil joins a slip ring that turns with the shaft. Brushes press on the rings and carry the current into the external circuit, here lighting a bulb.
Swap the slip rings for a split ring, a commutator, and the same machine gives pulsed direct current: a dynamo.
Questions and answers
What are the main parts of a generator?
A magnetic field, from magnets or field coils; a coil of wire, the armature, that turns in it; and a way to turn it, such as a turbine. Slip rings and brushes carry the current out.
What turns a generator?
Anything that can spin the shaft: steam from burning fuel, falling water in a dam, or the wind. In a steam turbine the steam pushes on blades fixed to the shaft.
What do the brushes do in a generator?
They press on the rings that turn with the coil, so the current can pass from the spinning coil to the wires that stay still.