What polarity should be used when the test shall be repeated with the applied DC voltage?

When repeating a test with applied DC voltage, using the opposite polarity is necessary to assess the performance characteristics of the device under different conditions. This practice helps identify any potential issues related to device behavior affected by the direction of the electric current. Analyzing how the device responds to both polarities can provide insights into rectification properties, potential leakage paths, or other anomalies that may not be evident when testing solely with one polarity.

Using the same polarity would not yield new information about the device's performance under varying conditions, while neutral and indeterminate do not apply in the context of testing with DC voltage, as there needs to be a defined reference of positive and negative. Thus, alternating between polarities is essential for thorough evaluation and ensuring accurate insights into the device’s electrical characteristics.