DC circuitsQuestion 884 of 1506

A DC source is suddenly connected across an unmagnetized inductor. What is the inductor voltage drop at the first instant?

  1. Zero
  2. Half the source voltage
  3. The full source voltage
  4. Twice the source voltage
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Correct answer: The full source voltage

The inductor resists the change in current at first, so it drops the whole source voltage and current starts at zero.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 15.1: Magnetic Fields and Inductance

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Questions last reviewed: 18 October 2026