SIGNAL LEVEL MONITORING CIRCUIT

PROBLEM TO BE SOLVED: To make accurately effectively regulable gain and offset voltage by only one time simple regulating procedure in a signal level monitoring circuit for outputting a voltage or current corresponding to the level of an input signal. SOLUTION: The signal level monitoring circuit comprises a first amplifying circuit 1-21 for outputting a predetermined level value v1 according to a regulation of an offset regulating voltage Vr when a voltage vi input from a monitoring detector 1-1 is a predetermined reference level, a second amplifying circuit 1-22 for setting an arbitrary gain, and a third amplifying circuit for outputting a predetermined monitoring output voltage vo according to a regulation of an offset regulation voltage Vof irrespective of the gain of the second amplifying circuit when the voltage vi is at the predetermined reference level.