bimetalu

Bimetal is a composite material made from two different metals joined together. Typically, these metals have significantly different coefficients of thermal expansion. This means that as the temperature changes, one metal expands or contracts more than the other. When the two metals are bonded together, this differential expansion or contraction causes the bimetal strip to bend. The degree of bending is proportional to the temperature change.

The most common application of bimetal is in thermostats. A bimetal strip is often shaped into a coil or a flat strip. As the temperature rises, the strip bends, and this movement can be used to break an electrical circuit, turning off a heating element or appliance. Conversely, as the temperature falls, the strip straightens or bends in the opposite direction, re-establishing the circuit and turning the appliance back on. This simple yet effective mechanism has been widely used in various temperature-regulating devices.

Beyond thermostats, bimetal finds use in circuit breakers as a tripping mechanism. Overcurrent in a circuit heats the bimetal strip. The resulting bending actuates a lever that opens the circuit, preventing damage. Bimetal is also employed in automotive applications, such as in some temperature gauges and automatic chokes, and in various industrial control systems where temperature-sensitive actuation is required. The specific metals used vary depending on the desired operating temperature range and sensitivity.