It is a temperature sensing element, a primary instrument, and a thermocouple directly measures the temperature. A closed circuit composed of two conductors with different composition materials. Due to the different materials, different electron densities generate electron diffusion, and after stable equilibrium, an electric potential is generated. When there is a gradient temperature at both ends, a current is generated in the circuit, generating thermoelectric electromotive force. The larger the temperature difference, the greater the current will be. After measuring the thermoelectric electromotive force, the temperature value can be determined. A thermocouple is actually an energy converter that can convert thermal energy into electrical energy.

The technical advantages of thermocouples: they have a wide temperature measurement range and relatively stable performance; High measurement accuracy, thermocouple in direct contact with the measured object, unaffected by intermediate media; Fast thermal response time and flexible response of thermocouples to temperature changes; The measurement range is large, and thermocouples can continuously measure temperature from -40 to+1600 ℃; Thermocouples have reliable performance and good mechanical strength. Long service life and convenient installation.

A thermocouple must be composed of two types of conductor (or semiconductor) materials with different properties but meeting certain requirements to form a circuit. There must be a temperature difference between the thermocouple measurement end and the reference end.

Solder two different types of conductors or semiconductors A and B together to form a closed loop. When there is a temperature difference between the two attachment points 1 and 2 of conductors A and B, an electromotive force is generated between the two, forming a current of a certain magnitude in the circuit. This phenomenon is called the thermoelectric effect. Thermocouples work by applying this effect.