Motor controlsQuestion 235 of 1506

How does a bimetallic strip temperature switch work?

  1. A small paddle wheel stops turning once it gets hot
  2. A magnet inside loses its strength when it is heated
  3. Two bonded metals expand unequally and bend
  4. A float rises as the liquid in the bulb expands
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Correct answer: Two bonded metals expand unequally and bend

The two bonded metals bend when heated or cooled. The bending moves the contact.

Source: Lessons in Electric Circuits IV: Digital (Kuphaldt), 4.1: Switch Types

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Questions last reviewed: 18 October 2026