What is applied to the vertical deflection plates of a cathode ray tube when a condition of unbalance exists during eddy current testing by the linear time base method?

In eddy current testing using the linear time base method, when a condition of unbalance exists, a sawtooth wave is applied to the vertical deflection plates of a cathode ray tube. This is essential for producing a visual representation of the test signal.

The sawtooth wave generates linear, continuous motion on the display, which is critical for indicating the amplitude and phase of the eddy current signals detected. As the test progresses, the introduction of the sawtooth waveform allows technicians to observe changes in signal strength that correlate with flaws or variations in material properties. This helps in accurately identifying the nature and extent of any detected anomalies.

Therefore, the sawtooth wave is integral to effectively translating eddy current data into a visual format conducive for analysis, making it the correct choice for this scenario.