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What is the Principle of Fast Thermocouples?
2022-07-14

What is a fast thermocouple?

Fast thermocouples are one of the most commonly used temperature detection elements in the industry. The working principle of fast thermocouples is based on the Seeback effect, that is, two ends of conductors of different compositions are connected into a loop. If the temperature of the two connection ends is different, the physical phenomenon of thermal current is generated in the loop.

fast thermocouples

What is the principle of fast thermocouples?

A fast thermocouple is a temperature sensing element. It is a one-time instrument. It directly measures the temperature and converts the temperature signal into a thermoelectromotive force signal. Then it is converted into the temperature of the measured medium through the electrical instrument (secondary instrument).

The basic principle of fast thermocouple temperature measurement is that two kinds of material conductors with different compositions form a closed loop. , When there is a temperature gradient at both ends, there will be current in the loop. At this time, there is an electromotive force between the two ends, the thermoelectromotive force, which is the so-called Seebeck effect.

Homogeneous conductors of two different compositions are hot electrodes. The end with the higher temperature is the working end, and the end with the lower temperature is the free end. The free end is usually at some constant temperature. According to the functional relationship between thermoelectromotive force and temperature, a fast thermocouple indexing table is made. The scale table is obtained with the free end temperature at 0°C. Different fast thermocouples have different scales.
A fast thermocouple welds two conductors or semiconductors A and B of dissimilar materials to form a closed loop.

When a third metal material is connected to the fast thermocouple loop, as long as the temperature of the two junctions of the material is the same, the thermoelectric potential generated by the fast thermocouple will remain unchanged. That is, it is not affected by the access of the third metal into the loop. Therefore, the measuring instrument can be connected to the fast thermocouple temperature measurement. After measuring the thermoelectromotive force, the temperature of the measured medium can be known.

That’s it for an introduction to fast thermocouples. If you have any questions about fast thermocouples, or if you are interested in our products, you are welcome to contact us at [email protected]