Explain Bimetals.
Bimetals: It is made of two metallic strips of not like metal alloys with various coefficients of thermal expansion. At a specific temperature the strip will bend and actuate a switch or a lever of a switch. The bimetal can be heatedly indirectly or directly. While heated the element bends therefore the metal with the greater coefficient of expansion is on the outside of the arc formed whereas with smaller coefficient is inside. While cooled the element bends in other directions. Alloys of nickel and iron with low coefficients of thermal expansion are utilized as one element of the bimetallic strip. The other element comprises materials containing high values of thermal expansion. Illustrations are iron, constantan, nickel and brass. Bimetallic strips are utilized in electrical apparatus and in devices as relays and regulators.