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 or timing chain, they convert mechanical energy into electrical energy via electromagnetic induction. Core components include a rotating rotor with field windings, a stationary stator containing armature windings, voltage regulators maintaining consistent output, and rectifier diodes converting AC to DC. Modern alternators utilize brushless designs for increased durability and efficiency, with output capacities ranging from 50 to 200+ amps depending on vehicle application. Precise voltage regulation and amperage output are critical for optimal system performance and component longevity.