DISTORTION AMPLIFIER

PURPOSE:To shorten the time until the balancing of a bridge circuit and to simplify the constitution of an autobalance circuit by applying a D/A conversion output with the opposite polarity from the output of a differential amplifier. CONSTITUTION:A voltage corresponding to deviation in balance that the bridge circuit BR has is led out of the differential amplifier DU and applied to a comparator COP. When a balance command signal BLA is supplied to a control logic element CL, the CL, the COP, and a D/A conversion part input a voltage corresponding to the deviation in balance that the BR has and applies the D/A conversion output to the offset adjustment terminal OF of the DU to execute a routine of sequential comparison type A/D conversion. The D/A conversion output is applied having the opposite polarity from the output of the BR containing the deviation in balance at the terminal OF.