Eddy current differential transducer for deep flaws evaluation

This paper presents a new differential eddy current transducer, which can be utilized to measure precisely depth of the flaws. A nearly linear dependence of the output signal amplitude on the flaw depth can be achieved by precise selection of an exciting frequency. In order to calibrate and prove usability of the newly developed transducer a set of experiments were carried out. The obtained results confirmed that, the linear relation between amplitude and flaw depth is obtained for a wide range of flaws' depths. It can be retained even in case of very deep flaws.