Eddy Current Testing (ET) Level I Practice Test

What is a reference plane in ET testing?

A defect-free area or calibration surface used to establish a baseline impedance against which other readings are compared.

In eddy current testing, readings depend on how the probe couples to the surface, which is affected by lift-off and surface condition. A reference plane is a defect-free area or calibration surface used to establish a baseline impedance. By measuring the impedance on this known-good region, you create a baseline that other readings are compared to. Deviations from this baseline in other areas can indicate defects, once you’ve accounted for lift-off and geometry. It isn’t just the mounting plane, nor a purely theoretical plane, nor a temperature-measuring plane.

The physical plane where the device is mounted.

A theoretical plane used in analysis with no real-world counterpart.

A plane at which temperature is measured.