What is a temperature sensor?
Temperature is a basic physical quantity, and all processes in nature are closely related to temperature. Temperature sensor is one of the earliest developed and most widely used sensors. The market share of temperature sensors greatly exceeds that of other sensors. From the beginning of the 17th century, people began to measure temperature. With the support of semiconductor technology, semiconductor thermocouple sensor, PN junction temperature sensor and integrated temperature sensor have been developed successively in this century. Accordingly, acoustic temperature sensors, infrared sensors and microwave sensors have been developed according to the interaction law of wave and matter.
If two conductors of different materials are connected to each other at a certain point, if the connection point is heated, the potential difference will appear at the unheated part. The value of this potential difference is related to the temperature of the measuring point at the unheated part and the material of the two conductors. This phenomenon can occur in a wide temperature range. If the potential difference is accurately measured and the ambient temperature of the unheated part is measured, the temperature of the heating point can be accurately known. It is called "thermocouple" because it must have two conductors of different materials. Thermocouples made of different materials are used in different temperature ranges, and their sensitivity is also different. The sensitivity of thermocouple refers to the change of output potential difference when the temperature of heating spot changes by 1 ℃. For most thermocouples supported by metal materials, this value is about 5-40 microvolts / ℃. Thermocouple sensor has its own advantages and disadvantages. Its sensitivity is relatively low, and it is easy to be affected by environmental interference signals and the temperature drift of preamplifier. Therefore, it is not suitable for measuring small temperature changes. Since the sensitivity of the thermocouple temperature sensor is independent of the thickness of the material, the temperature sensor can be made of a very fine material. Due to the good ductility of the metal material used to make the thermocouple, this fine temperature measuring element has a very high response speed and can measure the process of rapid change.
The temperature sensor is the most commonly used one among various sensors. The modern temperature sensor has a very small shape, which makes it more widely used in various fields of production practice and provides countless convenience and functions for our life.