Temperature sensor designed by the principle of metal expansion

　　 Metal will produce a corresponding extension after the ambient temperature changes, so the sensor can signal this reaction in different ways. Bimetallic sheet sensor The bimetallic sheet is composed of two pieces of metal with different expansion coefficients pasted together. As the temperature changes, material A expands more than another metal, causing the metal sheet to bend.

The curvature of 　　 bend can be converted into an output signal. As the temperature of the bimetal rod and metal tube sensor increases, the length of the metal tube (material A) increases, but the length of the unexpanded steel rod (metal B) does not increase, so that due to the change of position, the linear expansion of the metal tube can be To pass. In turn, this linear expansion can be converted into an output signal.

　　The sensor designed with the deformation curve of liquid and gas will change in volume when the temperature changes. Various types of structures can convert this change in expansion into a change in position, thus producing a change in position output (potentiometer, induced deviation, baffle, etc.).

　　 resistance sensor temperature sensor

　　 As the temperature changes, the resistance of metals also changes. For different metals, the resistance value changes every time the temperature changes by one degree, and the resistance value can be directly used as the output signal. There are two types of resistance changes. Positive temperature coefficient temperature increase = resistance value increase, temperature decrease = resistance value decrease, negative temperature coefficient temperature increase = resistance value decrease, temperature decrease = resistance value increase

　　Thermocouple sensor temperature sensor

　　The thermocouple consists of two metal wires of different materials, welded together at the ends. By measuring the ambient temperature of the unheated part, the temperature of the heating point can be accurately known. Since it must have conductors of two different materials, it is called a thermocouple. Thermocouples made of different materials are used in different temperature ranges, and their sensitivity is also different. The sensitivity of a thermocouple refers to the amount of change in the output potential difference when the heating point temperature changes by 1°C. For most thermocouples supported by metal materials, this value is about 5-40 microvolts/°C.

　　 Since the sensitivity of the thermocouple temperature sensor has nothing to do with the thickness of the material, the temperature sensor can be made with very fine materials. Also, because the metal material used to make thermocouples has good ductility, this kind of fine temperature measuring element has a very high response speed and can measure rapid changes.