Thomas R. Hay (PhD, PE) and Suhaib Zafar Introduction Eddy Current Testing (ECT) utilizes the phenomenon of electromagnetic induction — a magnet inducing electric currents in a conducting material (typically metals) that is moving relative to the magnet, or an alternating current (AC) causing a time-varying magnetic field [1]. The induced current is known as eddy current , and this in turn affects the current in the magnet. Typically, the magnet used is a coil, with alternat