What does a "differential approach" refer to in Eddy Current Testing?

The differential approach in Eddy Current Testing refers to the technique of using multiple frequencies to enhance the detection of defects. By employing various frequencies, testers can obtain a more comprehensive understanding of the material under inspection and improve sensitivity to defects that may not be easily detected at a single frequency. Different frequencies interact with the material in unique ways, allowing for the differentiation between normal material characteristics and any anomalies, such as cracks or changes in conductivity.

Using multiple frequencies not only aids in identifying defects but also helps in classifying them based on their sizes and types. This multifrequency approach is particularly beneficial in complex geometries or when inspecting materials with varying properties, as it increases the likelihood of detecting subtle defects that might be missed if only one frequency were utilized.

This technique contrasts with other options that focus on different aspects of Eddy Current Testing, such as dynamic adjustment of the probe distance or the simplicity of using a single frequency, which may limit detection capabilities. Therefore, the differential approach is a key strategy for enhancing the accuracy and effectiveness of defect detection in Eddy Current Testing.