The alternator works by turning mechanical energy into electrical energy. When your engine is on, it powers a drive belt that rests on a pulley attached to the alternator. … The rectifier converts that AC power into DC power, which activates your car’s electrical systems.
Car batteries operate on one-way direct current (DC) electricity, while alternators output alternating current (AC) electricity, which occasionally flows in reverse. [6] So prior to going to the voltage regulator, power intended for the battery goes through a diode rectifier to turn into DC.




