The alternator is an essential component in a car engine's electrical system. In essence a car's alternator charges the battery and powers the car's electrical system when its engine is running.
It is a component that can sometimes fail and your engine may appear dead if it does. All types of alternators for every make and model of car are available in the event of malfunction. As an essential component in your engine, it is worth investing in a top quality alternator and not a cheaper, 'pattern' alternative.