What is the working principle of thermocouple thermal resistance?

Two different components of the conductor (called a thermocouple wire or a hot electrode) are joined together at both ends. When the junction temperature is different, an electromotive force is generated in the circuit. This phenomenon is called the thermoelectric effect. The electromotive force is called thermoelectric power. Thermocouples use this principle for temperature measurement, in which the end that is used directly to measure the temperature of a medium is called the working end (also called the measuring end), and the other end is called the cold end (also called the compensation end); the cold end and the display The meter or associated meter is connected and the meter indicates the thermoelectric potential generated by the thermocouple.

A thermocouple is actually an energy converter. It converts thermal energy into electrical energy and measures the temperature using the resulting thermoelectric potential. The thermoelectric potential of a thermocouple should be noted as follows:

1: Thermocouple thermoelectric potential is the difference of the temperature function of the two ends of the thermocouple working end, not the function of the temperature difference between the cold junction and the working end of the thermocouple;

2 : The thermoelectric potential generated by the thermocouple, when the material of the thermocouple is uniform, has nothing to do with the length and diameter of the thermocouple, but only related to the composition of the thermocouple material and the temperature difference at both ends;

3: When the two thermocouple wire components of the thermocouple are determined, the thermocouple thermoelectric potential is only related to the temperature difference of the thermocouple; if the temperature of the thermocouple cold junction is kept constant, the thermoelectric potential of the thermocouple is only The single-valued function of the working temperature. Two different material conductors or semiconductors A and B are welded together to form a closed loop as shown. When there is a temperature difference between the two sticking points 1 and 2 of the conductors A and B, an electromotive force is generated between the two sticking points 1 and 2 so that a current of a size is formed in the loop. This phenomenon is called a thermoelectric effect. Thermocouples use this effect to work.