Question

A periodic voltage waveform observed across a load on oscilloscope is shown in figure below. A (PMMC) voltmeter connected across load will show______ V.

• A. 4.6

Answer 1

The correct option is A 4.6
PMMC reads only average value,

$V_{avg}=\frac{Areaundercurve}{Totaltime}$

$=\frac{(\frac{1}{2}\times 28\times 12)+(-\frac{1}{2}\times 4\times 16)+(8\times 6)}{40}=\frac{168-32+48}{40}=4.6V$

$V_{avg}=4.6V$