A thermocouple is a commonly used temperature measuring element in temperature measuring instruments, which measures temperature through the voltage difference generated by temperature changes. 

Working principle: It is composed of two different conductors forming a loop. When the temperatures at the two junctions are different, an electromotive force will be generated in the loop. The direction and magnitude of this electromotive force are related to the material of the conductors and the temperatures of the two junctions. 

Structure: It is usually composed of main parts such as thermodes, insulating sleeve protection tubes and junction boxes. 

Advantages: 

Wide range: It can measure temperatures ranging from extremely low to extremely high. 

High sensitivity: It can measure tiny temperature changes. 

Rapid response: It can respond quickly to temperature changes. 

Durability: It is resistant to high temperature, corrosion and vibration. 

Application: It is widely used in fields such as temperature control systems, heat treatment furnaces, medical equipment, burners, and engine monitoring.