Red Seal Electrician Practice
Motor controlsQuestion 106 of 1506

Two normally closed contacts are wired in series with a lamp. When is the lamp on?

  1. When either contact is actuated
  2. Only when neither contact is actuated
  3. When both contacts are actuated
  4. Whenever one of the contacts is unactuated
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Correct answer: Only when neither contact is actuated

This is the NOR function. Either contact opening breaks the path.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.2: Digital Logic Functions

Practice motor controls

Questions last reviewed: 18 October 2026