PHASE ADJUSTMENT CIRCUIT OF WATTHOUR METER

摘要

PROBLEM TO BE SOLVED: To provide a phase adjustment circuit of watthour meters capable of maintaining a constant gain regardless of the adjustment of the amount of phase correction.

SOLUTION: The phase adjustment circuit 3a is constituted of an operational amplifier OP1; a resistor R1 connected between a noninverting input terminal of the operational amplifier OP1 and a ground level; a capacitor C1 having one end connected to the noninverting input terminal of the operational amplifier OP1; a resistor R2 connected between the noninverting input terminal of the operational amplifier OP1 and the other end of the capacitor C1; and a resistor R3 connected between an output terminal and the noninverting input terminal of the operational amplifier OP1. By adjusting each value of the capacitor C1 and the resistor R1, the amount of a phase advance (amount of phase adjustment) of a voltage detection signal V3a to a voltage detection signal V1 is adjusted. By adjusting each value of the resistor R2 and the resistor R3, a gain (V3a/V1) of the operational amplifier OP1 is adjusted.

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