a multi - function alternating current meter having a voltage probe and clamp type current probe for sampling voltage and current of a alternating current line without physically breaking into the line . components include the two input probes which are connected to a squaring circuit and compensated low pass active filters which are arranged for feeding the respective output signals into an analog summing amplifier . subsequently the signals are fed into a calibrated output indicator . a scaled multiplier and phase lead / lag detector are included in the circuit . switches are capable of rerouting the input signals through various components , and the various outputs are individually applied to the calibrated output indicator to indicate the a . c . line &# 39 ; s power factor , phase angle , true power , apparent power , voltage , current , or lead / lag status , as selected .