To provide a current transformer signal detection circuit capable of increasing voltage for detection at the secondary side of a current transformer(CT) without any change of a ratio of current transformation as well as without causing an increase in resistance as a burden on the secondary side of the CT.
Regarding the signal detection circuit of CT 2 for converting current flowing across a primary conductor 1 to voltage for the detection thereof, the negative terminal of an operational amplifier 5 is connected to the secondary positive electrode of the CT 2, and the positive terminal thereof is connected to the secondary negative electrode of the CT 2 and the ground. Also, a signal amplification resistor 6 is connected across the negative terminal and the output terminal of the operational amplifier 5. In addition, a reverse-loaded parallel circuit made of two diodes 3 and 4 is connected across the positive and negative terminals of the operational amplifier 5, so as to prevent the occurrence of excessive voltage at the secondary side of the CT 2.
SAITO HIDEKI
FURUTA TAKU
