TransformersQuestion 883 of 1506

How can DC be used to induce a voltage in a second coil?

  1. Increase the DC voltage slowly forever.
  2. Switch the DC on and off so that it pulses.
  3. Connect the DC with reversed polarity to the core.
  4. Use a wire with lower resistance.
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Correct answer: Switch the DC on and off so that it pulses.

The pulsing makes the flux change, which induces voltage at each pulse.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 14.6: Mutual Inductance

Practice transformers

Questions last reviewed: 18 October 2026