A bimetallic switch is a control engineering component which causes a certain action once a defined temperature is reached, e.g. switching off a process in order to avoid overheating. It is based on the fact that under changing thermal conditions every metal expands or contracts according to a fixed thermal expansion coefficient. Hence the bimetal, a component made of two connected strips of different metals (e.g. steel and zinc), bends when the temperature changes. Once the bending strain reaches the limit defined by the designer of the switch, the bimetallic switch is activated.