Alternators are engine-driven generators supplying direct current (DC) electricity to power vehicle electrical systems and recharge the battery. Typically mounted to the engine block and driven by a serpentine belt, they convert mechanical energy into electrical energy via electromagnetic induction. Core components include a rotating rotor with field windings, a stationary stator housing the output windings, and a voltage regulator maintaining consistent output. Modern alternators utilize rectifying diodes to convert AC voltage generated within the stator to usable DC voltage. Output amperage ranges vary based on vehicle application and electrical load demands, with typical values between 55-180 amps.