voltage regulator

A device which maintains the correct voltage level in a vehicle's electrical system by preventing the circuit voltage from exceeding a predetermined safe value. When the battery needs charging the regulator cuts resistance out of the generator field circuit, thus increasing the flow of current in that circuit, with the further result that output is increased. When the battery becomes fully charged, the resistance is cut back into the field circuit so that the charging rate is decreased. As the engine speed increases, the alternator increases and generates more voltage. Unchecked, the alternator might put out so much voltage that bulbs and other electrical components might burn out. To a certain extent, the battery acts as a voltage regulator, but it too can be damaged by an electrical system which does not have an operating voltage regulator.