Abstract: The generator regulator includes a transistor power end stage (14) connected to the excitation winding (12) of the generator to provide a pulsed excitation current that passes through the excitation winding during operation and a device for activating and deactivating the transistor power end stage to turn on and off the excitation current in order to provide a predetermined pulse width for the pulsed excitation current passing through the excitation winding so as to maintain a constant output voltage. The device for activating and deactivating the transistor power end stage includes a comparator (16) for comparing a saturation voltage (U.sub.SAT) of the transistor power end stage (14) picked up between the transistor power end stage and the excitation winding with a reference voltage (U.sub.