What does "AC" stand for in relation to electrical applications in NDT?

In the context of electrical applications in Non-Destructive Testing (NDT), "AC" stands for Alternating Current. This term is fundamental as it describes the type of electrical current that reverses direction periodically, in contrast to direct current (DC), which flows in a single direction.

Alternating current is particularly relevant in various NDT techniques, such as eddy current testing and ultrasonic testing, where the electrical signal's characteristics influence the response of the test material. For instance, in eddy current testing, AC is essential for inducing currents in conductive materials, which helps in detecting surface and subsurface defects.

The other options, while related to electrical concepts, do not accurately define "AC" in this specific context. Alternating Circuit is not a standard term used in NDT, Active Current is not a recognized term in electrical practices, and Amplitude Control refers to managing the strength of a signal rather than the type of current. Thus, recognizing "AC" as Alternating Current is crucial for understanding various NDT techniques and their operational principles.