TEMPERATURE COMPENSATION SYSTEM OF LIGHT MEASURING CIRCUIT

Disclosed is a temperature compensation system for light measuring circuits. Said system compensates for the change, over temperature, of the output of the light measuring circuit by applying a bias source with a predetermined temperature coefficient. The system is designed so the bias voltage source is derived from the V.sub.BE (base to emitter voltage) difference between a pair of transistors, which difference is generated by the difference of current density at the junction of the pair of transistors obtained by flowing a pair of currents with a constant ratio independent of temperature.