Introduction to thermocouples
The thermocouple is a kind of temperature sensing element, it is a primary instrument, it directly measures the temperature, and converts the temperature signal into a thermoelectromotive force signal, which is converted into the temperature of the measured medium through an electrical instrument (secondary instrument). The basic principle of thermocouple temperature measurement is that two different components of material conductors form a closed loop. When there is a temperature gradient at both ends, current will flow through the loop. At this time, there is an electromotive force-thermoelectromotive force between the two ends. This is the so-called Seebeck effect. Two homogeneous conductors with different components are thermoelectrodes, the end with a higher temperature is the working end, the end with a lower temperature is the free end, and the free end is usually at a certain constant temperature. According to the functional relationship between thermoelectromotive force and temperature, a thermocouple index table is made; the index table is obtained when the free end temperature is at 0℃, and different thermocouples have different index tables.
Thermocouple, commonly known as temperature measuring wire, is used to measure temperature. It is a combination of two different materials of wire. The thermal expansion coefficients of these two materials are different. After heating, a certain electromotive force will be generated. The temperature measuring instrument passes This slight change is converted into a temperature display!
