Red Seal Electrician Practice
TransformersQuestion 1118 of 1506

A transformer has a 4:1 turns ratio (primary to secondary). A 2 ohm load is on the secondary. What impedance does the source see?

  1. 8 ohms
  2. 0.5 ohm
  3. 32 ohms
  4. 128 ohms
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Correct answer: 32 ohms

Impedance changes by the square of the turns ratio. 4 squared is 16, and 2 ohms x 16 = 32 ohms.

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

Practice transformers

Questions last reviewed: 18 October 2026