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Regarding the difficult problems of thermocouples, the specific content is as follows:
1. What is the precise measurement principle of thermocouple?
The working principle of the thermocouple is based on the Seebeck (seeback) effect, that is, two conductors with different components are combined to form a control circuit. If the temperature of the two terminals is different, a physical change of thermal current will be generated in the control circuit.
The thermocouple is composed of two different wires (thermoelectric grades), and one end of them is welded to each other to form the measuring end of the thermocouple (also known as the working end). Insert it into the substance whose temperature is to be measured; and the other end of the thermocouple (the reference end or the random end) is connected to the digital display instrument. If there is a temperature difference between the precise measurement end of the thermocouple and the reference end, the digital display instrument will emphasize the thermally induced electromotive force caused by the thermocouple.
2. What is the precise measurement principle of thermal resistance?
Thermal resistance is to use the characteristic that its resistance also changes when the temperature of metal conductor or semiconductor material changes to accurately measure the temperature. The heated part of thermal resistance (temperature sensor component) is evenly wound with thin iron wire It is produced on a frame made of insulating layer material or on a silicon wafer according to the laser magnetron sputtering process. When the measured substance has a temperature gradient direction, the measured temperature is the average temperature of the material layer within the category of the temperature sensor component.
3. How to choose thermocouple and thermal resistance?
Select according to the temperature measurement range: generally select thermocouples above 500°C, and generally select thermal resistors below 500°C;
Selection based on measurement accuracy: select thermal resistance for high precision requirements, and select thermocouple for low precision requirements;
Select according to the detection range: the temperature measured by thermocouples generally refers to the "spot" temperature, and the temperature measured by thermal resistance generally refers to the average temperature of the indoor space
