Temperature is a physical quantity characterizing degree of hot and cold objects, is a very important and common industrial and agricultural production parameters. Temperature measurement and control to ensure product quality, improve production efficiency, energy conservation, production safety, promoting the development of the national economy plays a very important role. Because of the universality of the temperature measurement, temperature sensors, the number of various sensors at the top, about 50%.
Temperature sensor through the object certain characteristics with temperature change measured indirectly. Many materials, components, properties vary with temperature, so it can make the equivalent of the temperature sensor. Temperature sensors of physical parameters caused by temperature changes: expansion, resistors, capacitors, and EMF, magnetic properties and thermal noise, frequency, optical properties, and so on. With the development of production, new temperature sensor will continue to emerge.