Electrical generators that produce alternate current.
Alternators are electrical generators that produce alternate current. In the simplest form, they are fixed coil with moving magnetic element, like a magnet. Other constructions exist es well. The moving magnectic field induces electrical current on the coils element.
The term "alternator" is most often used to describe an AC generator with an integrated rectifier used to provide DC power for automotive use. The term "synchronous generator" is most applied to power station generators and used in engineering text books and other scholarly contexts.