Alternator
An alternator is a type of electric generator used in modern vehicles to charge the battery and to power the electrical system when its engine is running.
Until the 1960s, cars used DC dynamo generators with commutators. As silicon diode rectifiers became widely available and affordable, the alternator gradually replaced the dynamo. This was encouraged by the increasing electrical power required for cars in this period, with increasing loads from larger headlamps, electric wipers, heated rear window and other accessories.