Research on the device of differential excitation type eddy current testing for metal defect detection

A differential excitation type sensor is introduced based on the eddy current principle for detecting metal defects, to improve the detection performance of the sensor system by optimizing the circuit of detection system. Using Q235 specimen as the detection object, aiming to detect and analyze the cracks of different depth and width and then to study the influence of excitation frequency, excitation amplitude and lift-off on the results. The test results showed that the differential excitation type eddy current testing device can be used for detecting defects on metal with high sensitivity.