An automobile voltage regulator controls the voltage produced by the car’s alternator to recharge the battery. The regulator forces the alternator to maintain a voltage of between 13.5 volts and 14.5 volts. This is sufficient to recharge the battery safely while protecting the electrical circuits and components of the car, including the wiring system, lights, motors that drive power accessories and stereo.
Starting the Engine
Voltage from the battery starts the car when the ignition switch is turned. Voltage pours through the starter to get the car running by causing a controlled explosion in the engine combustion chamber.
Powering the Alternator
Once the car is running, a drive belt causes a spinning rotor to turn inside the alternator, which acts like a generator to produce power. The power moves from the alternator to the battery by way of the voltage regulator.