Bimetal Dial Thermometer

A bimetal is a component made of two connected strips of different metals (e.g. steel and zinc). Every metal has a fixed thermal expansion coefficient, which is different for each metal. Thus, when the temperature changes, this will cause a different expansion in each metal, which bends the bimetal. As the thermal expansion coefficient is known, it is possible to tell the temperature from the amount of bending caused in the bimetal. Therefore, in a bimetal dial thermometer the bimetal is connected, via a mechanical measuring system, with a pointer indicating the temperature on a graduated disc.

Go back