What is the significance of signal amplitude in Eddy Current Testing?

The significance of signal amplitude in Eddy Current Testing lies in its representation of the strength of the induced eddy currents. When an alternating current passes through a coil placed near a conductive material, it generates eddy currents within the material. The amplitude of the resulting signal is directly related to the magnitude of these eddy currents, which can provide crucial information about the electrical and material properties of the test specimen.

Higher amplitudes generally indicate stronger eddy currents, which might suggest good conductivity and less material thickness or fewer defects. Conversely, a lower amplitude can indicate a change in material properties, such as the presence of cracks, changes in material composition, or surface condition. Therefore, analyzing the amplitude allows an inspector to assess the presence of discontinuities or variations in the material being tested.

Understanding this concept is critical, as it helps technicians interpret the test results accurately, leading to better assessments of the integrity of the components being examined.