How does lift-off affect the amplitude of the eddy current signal?

An increase in lift-off reduces the amplitude of the eddy current signal. Lift-off refers to the distance between the probe and the conductive material being tested. As the lift-off distance increases, the electromagnetic coupling between the eddy current probe and the material decreases, leading to a weaker eddy current signal. This diminished coupling results in a lower amplitude reading.

Understanding the impact of lift-off is crucial for accurately interpreting the results of eddy current testing. Increased lift-off can mask the presence of flaws or variations in material properties because the signal becomes less sensitive to changes within the test material. Therefore, maintaining an optimal lift-off distance is important for achieving reliable and meaningful test results.