Which of the following factors can introduce significant noise in eddy current testing results?

In Eddy Current Testing (ET), multiple factors can contribute to noise or interference in the results, making it essential for technicians to be aware of various influences on the measurement accuracy.

Temperature fluctuations can significantly affect the electrical conductivity and magnetic permeability of the materials being tested. As the temperature changes, it can lead to variations in the eddy current response, which may introduce noise in the readings that need to be carefully interpreted or compensated for.

Surface conditions of the test material are equally important. Factors such as roughness, cleanliness, coatings, or corrosion can alter the way eddy currents are induced and the ensuing signals captured. Irregularities on the surface can cause scattering of the eddy currents, resulting in inconsistent or misleading signals that can misrepresent the condition of the material being examined.

The movement of the testing equipment also plays a role. If the probe or the material being tested is not stable or moves while measurements are being taken, it can introduce additional noise. This movement can lead to variations in the generated eddy current fields and their responses, therefore distorting the results.

Given that each of these factors—temperature fluctuations, surface conditions, and movement of the equipment—can independently contribute to noise, the correct answer encompasses all of them, affirm