Red Seal Electrician Practice
TransformersQuestion 1085 of 1506

A transformer has a 10:1 turns ratio (primary to secondary). The primary is connected to 120 V. What is the secondary voltage?

  1. 12 V
  2. 1200 V
  3. 120 V
  4. 1.2 V
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Correct answer: 12 V

Voltage follows the turns ratio. With 10 times more turns on the primary, the secondary has one tenth of the voltage: 120 V / 10 = 12 V.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.2: Step-up and Step-down Transformers

Practice transformers

Questions last reviewed: 18 October 2026