Red Seal Electrician Practice
Motor controlsQuestion 97 of 1506

What does a watchdog timer relay do?

  1. It gives repeating on and off pulses while the coil is energized
  2. It gives one output pulse for each time the coil is energized
  3. It opens after a set delay when the coil is first energized
  4. It changes its contacts if its coil is not regularly cycled on and off
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Correct answer: It changes its contacts if its coil is not regularly cycled on and off

It can monitor a computer: if the computer locks up, the signal stops cycling and the relay times out.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 5.3: Time-delay Relays

Practice motor controls

Questions last reviewed: 18 October 2026