What’s thermocouple and it’s basic principle
Thermocouple is a temperature sensor, is an instrument, it directly measures the temperature, and the temperature signal into a thermoelectric power signal, through the electrical instrument (secondary instrument) into the measured medium temperature.
The basic principle of thermocouple temperature measurement is composed of two different components of the material composition of the closed loop conductor, when there is temperature gradient at both ends, the circuit will have a current through, then between the two ends there Seebeck electromotive force - thermal EMF, This is the so-called Seebeck effect. Two different components of the homogeneous conductor for the hot electrode, the higher the temperature end of the work side, the lower end of the temperature free end, the free end is usually at a constant temperature. According to the thermoelectromotive force and temperature as a function of the thermocouple indexing table; indexing table is the free end temperature at 0 ℃ under the conditions obtained, different thermocouples with different index table.