Inside The Alternator, Alternator Working Principle and Circuit Diagram 

What is alternator function ?
Alternator will produce electricity for vehicle needs. This component is very important because it is the only one who serve electricity continuously.
The current from alternator, store in battery. so that the battery is always fully charged.
then how alternator work ?
in simple, alternator work if the magnetic field rotate inside the coil. It make the coil has current flow.
to be clearer, see the following animation.