DETECTION CIRCUIT FOR CIRCUIT BREAKER

摘要

PROBLEM TO BE SOLVED: To provide a detection circuit for a circuit breaker capable of detecting a voltage or a current of a circuit with accuracy even when a noise is included in a voltage detection signal or a current detection signal.SOLUTION: A detection circuit for a circuit breaker includes: a detection sensor 20 detecting a voltage or a current of an AC power circuit and outputting a detection signal; a low-pass filter circuit part 30 removing a high-frequency component of the output signal of the detection sensor 20, and then outputting it; an offset removal circuit part 40 removing a DC offset of the output signal of the low-pass filter circuit part 30, and then outputting it; an amplifier circuit part 50 amplifying the output signal of the offset removal circuit part 40, and then outputting it; and a comparison circuit part 100 outputting a breaking control signal so that a circuit breaker 10 is operated to a breaking position when the output signal of the amplifier circuit part 50 is not smaller than a reference voltage.