Red Seal Electrician Practice
TransformersQuestion 245 of 1506

Why is a voltmeter on a potential transformer made with a high input impedance?

  1. It loads the PT lightly, so the ratio stays true
  2. It doubles the voltage that the meter sees
  3. It lets the PT carry a large added load
  4. It removes the need for a fuse on the PT primary
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Correct answer: It loads the PT lightly, so the ratio stays true

A meter that draws very little current keeps the loading on the PT small, so the voltage ratio stays accurate.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.7: Special Transformers and Applications

Practice transformers

Questions last reviewed: 18 October 2026