Fully Transistorized Regulator

In a fully transistorized regulator there are no relays used. It is made up of solid state electronic devices which make it a voltage sensitive electronic switch. A large transistor is in series with the alternator field winding and a control circuit which senses the system voltage. The control circuit turns the large transistor on and off as required to vary the alternator field current. Some regulators of this type provide for adjustment of the output voltage. Others are sealed and must be replaced if the alternator output voltage is not within limits.