Meters and troubleshootingQuestion 918 of 1506

An average-responding AC meter, calibrated for sine waves, measures a distorted non-sinusoidal voltage. What can you say about its reading?

It may not be the true RMS value.
It is always the exact RMS value.
It is always the peak value.
It is always zero.

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Correct answer: It may not be the true RMS value.

The needle responds to the average value. The scale assumes a sine wave, so another shape gives a wrong RMS reading.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 1.3: Measurements of AC Magnitude

Questions last reviewed: 18 October 2026

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