Red Seal Electrician Practice
Motor controlsQuestion 29 of 1506

Which devices can a PLC use to switch its outputs?

  1. A transistor, a TRIAC or a relay
  2. A thermocouple, a TRIAC or a fuse
  3. A shunt, a transistor or a capacitor
  4. A diode, a reed switch or a fuse
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Correct answer: A transistor, a TRIAC or a relay

The PLC computer drives a transistor, TRIAC or electromechanical relay for each output.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 6.6: Programmable Logic Controllers (PLC)

Practice motor controls

Questions last reviewed: 18 October 2026