Bimetallic thermometer principle

Bimetallic thermometer temperature element consists of two layer coefficient of linear expansion different, sheet metal lap welding together made, coefficient of linear expansion big pieces of metal called active layer, and the other a piece of it is called passive layer, element end fixed and the other end is for free end, when measured temperature change, as a result of two layer sheet metal coefficient of linear expansion is different, the free end will be combined moment and bending (or called deformation), the variable curvature and composition bimetallic strip material physical properties, length for each layer thickness, the temperature is concerned, and has nothing to do with width. When the temperature designed, bimetallic thermometer  strip material and geometric size determined, so variable curvature only relates to temperature, if the free end with the drive mechanism, cursors, and taking the temperature mark of the scale, which can directly show temperature and value.