Eddy current sensor compensating circuit, has sensor unit, where amplitude and phase of transmission signal is changed against another transmission signal so that output signal of sensor unit is changed or compensated to zero

摘要

The circuit has a sensor unit (1) receiving a transmission signal of same frequency and same signal shape using a power amplifier (4) adjacent to another transmission signal. An amplitude and a phase of the former signal is changed against the latter signal such that an output signal of the sensor unit is changed or compensated to zero, where the sensor unit is provided with or not provided with a selected test object. Two transmitting channels separately supplies two excitation windings of an eddy current coil unit.