Which electrical parameters are essential for interpreting eddy current signals in ET?

The essential electrical parameters for interpreting eddy current signals in eddy current testing (ET) are impedance, reactance, and resistance. These parameters give insight into how the eddy currents interact with the materials being tested.

Impedance is the total opposition that the circuit offers to the flow of alternating current and is comprised of resistance and reactance. Reactance, which can either be inductive or capacitive, describes how the circuit behavior changes with frequency, affecting the eddy currents' interaction with the material's properties. Resistance measures how much a material opposes the flow of current regardless of frequency.

In the context of eddy current testing, understanding these parameters is crucial because they directly influence the response of the instrument to defects, material characteristics, and the overall integrity of the test specimen. Variations in impedance and its components can reveal information about structural integrity, such as the presence of cracks, corrosion, or changes in material properties. Hence, these three parameters provide a framework for analyzing the data collected during eddy current tests effectively.