Electrical Engineering XYZ MCQs
Potentiometer method of DC voltage measurement is more accurate than direct measurement using a voltmeter because:
- It uses centre zero galvanometer instead of voltmeter
- It loads the circuit moderately
- It does not load the circuit at all
- It loads the circuit to maximum extent
Correct answer: 3. It does not load the circuit at all
Explanation: The potentiometer method of DC voltage measurement is more accurate than using a voltmeter because it does not load the circuit at all. Unlike voltmeters, which have a finite resistance and can draw current from a circuit, altering its conditions, a potentiometer measures voltage by balancing an unknown voltage against a known one without drawing current. This “null method” results in no circuit loading, making the potentiometer effectively have infinite input impedance during measurement. This ensures that the voltage measured is not affected by the measurement device, leading to highly accurate readings reflective of the true circuit conditions.