Red Seal Electrician Practice
TransformersQuestion 1097 of 1506

Two windings of a transformer have their polarity dots at matching ends. What is the phase shift from primary to secondary?

  1. 90 degrees
  2. 0 degrees
  3. 180 degrees
  4. 360 degrees lagging
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Correct answer: 0 degrees

Dots at the same ends mean the instantaneous polarities are the same. The voltages are in phase.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.4: Phasing

Practice transformers

Questions last reviewed: 18 October 2026