Question

Rectifier moving coil instrument responds to:

• A. peak value, irrespective of the nature of the waveform
• B. average value, for all waveforms
• C. rms value, for all waveforms
• D. rms value, for symmetrical square waveforms

Hint:

Rectifier-type instruments always respond to the \textbf{average value} of the waveform, not RMS or peak values.

Answer 1

The Correct Option is B

Rectifier-type moving coil instruments are used for measuring alternating currents or voltages.
These instruments use a rectifier (usually a diode) to convert AC into a unidirectional current before passing it through the moving coil.
Since the rectifier only allows current in one direction, the coil responds to the average value of the waveform (usually over a half cycle for full-wave rectifiers).
Therefore, regardless of the waveform shape (sine, triangular, etc.), the instrument scale is calibrated based on average values.
They do not respond to RMS or peak values directly.