In eddy current testing using the linear time-base method, what is applied when there is an unbalance condition between the test specimen and reference standard?

In eddy current testing using the linear time-base method, applying a sinusoidal wave is crucial for accurately representing the conditions being tested. This technique allows for the detection of changes in the impedance of the coil, which can occur due to variations in material properties or geometry between the test specimen and reference standard.

The sinusoidal wave is used because it provides a continuous and smooth signal that is essential for analyzing the response of the eddy current system. This response can be analyzed to identify discrepancies between the test and the reference, indicating potential defects or variations in the material being examined. By focusing on the sine wave, the system can derive meaningful data from the unbalanced conditions and adjust its readings accordingly.

The other options do not provide the same effectiveness in identifying and quantifying impedance changes. For example, a sawtooth wave and square wave offer different characteristics that do not align with the needs of eddy current testing setups that rely on precise, continuous measurements. The absence of voltage would simply mean no measurement could be taken, which defeats the purpose of testing altogether.