Abstract: A pulsed light signal receiver comprises a photo-sensitive transistor having a base and a collector and an emitter; a load resistance in the collector circuit and a constant current device in the emitter circuit. A capacitor shunting the constant current device over a predetermined range of signal frequencies renders the transistor gain high for such frequencies. The constant current device may be a field effect transistor with its gate at ground potential and a resistance in the source to ground circuit selected to determine the idling current of the FET and provide thermal stability for the photo-transistor circuit. A low impedance, balanced-to-neutral, output is provided.