AC and DC Generators

An AC generator is made by winding loops of wire on a rotating shaft between the poles of a magnet. When the coil rotates, the wires in the coil cut the magnetic field and voltage is induced in a direction given by the rRight Hand Rule. The voltage produced by the motor is alternating voltage, and reverses direction every time the coil rotates by half a turn.
The voltage is maximum when the coil is horizontal, since the coil cuts the field at a maximum rate, and minimum when the coil is vertical.
If the ends of the coil are allowed to change contacts with every half turn, then the direction of the voltage in the coil changes as the ends of the wires change contacts, and the coil continues to flow in the same direction. This is done by using brushes and a slip ring. Connecting the generator to an external circuit allows a current to flow.

The size of the induced voltage can be increased by
1. Rotating the coil faster.
2. Using a stronger magnet.
3. Using a coil with more turns.
4. Increasing the area of the coil