Abstract: In an azimuth reference system including a flux valve coupled to a synchro stator and a directional gyro having its outer gimbal mechanically coupled to the synchro rotor, a low power electronic slaving circuit having its input electrically coupled to the rotor of the synchro and its output coupled to a torquer for slaving the directional gyro into synchronism with the flux valve. The low power electronic circuit includes a phase compensated amplifier coupled between the synchro rotor and a demodulator for producing a bipolar slaving error signal which is coupled through a high gain amplifier to parallel connected coils in the torquer. A threshold detector circuit responsive to the speed of the gyro rotor controls a limiter feedback circuit in the high gain amplifier thereby limiting its gain when the gyro rotor has attained a predetermined speed.