thermocouple working principle and construction
The industrial thermocouple is used as a transducer for temperature measurement and adjustment, which is usually used with display instruments or electronic modulators. It can directly measure - 40 ~ 1700 ℃ in the process of various production within the scope of the liquid, steam and gas medium, as well as the temperature of the solid surface.
Chose two different kinds of metal or wire A and B as thermode. One end of the welding is as the measuring end, and the two ends of the connection display are called the displaying end. When measuring end and displaying end not at the same temperature,it can produce thermoelectric potential EAB (t, t0). When t0 = 0 ℃ :
the EAB (t, 0) = the EAB (t) = f (t)
The thermoelectric potential of thermocouple increases as the temperature of the measuring end increases. The size of the thermoelectric potential is only related to the material of the thermocouple conductor and the temperature of the two ends, which is independent of the length and diameter of the thermal electrode.
So you measure the thermoelectric potential and you get the temperature of the object being tested.