The main purpose of the temperature sensor
Source：Sentech Hits： Date：2018.03.28
Temperature is a physical quantity that characterizes the degree of cold and heat of an object. It is a very important and universal measurement parameter in industrial and agricultural production. Temperature measurement and control play a very important role in ensuring product quality, improving production efficiency, saving energy, producing safety, and promoting the development of the national economy. Due to the universality of temperature measurement, the number of temperature sensors ranks first among various sensors, accounting for about 50%.
Temperature sensors are indirectly measured by changing a characteristic of an object as the temperature changes. The characteristics of many materials and components change with temperature, so there are many materials that can be used as temperature sensors. Temperature sensors cause physical parameter changes with temperature: expansion, resistance, capacitance, and electromotive force, magnetic properties, frequency, optical properties, and thermal noise. With the development of production, new temperature sensors will continue to emerge.
Since the range of temperature measurement in industrial and agricultural production is extremely wide, from several hundred degrees below zero to thousands of degrees above zero, temperature sensors made of various materials can only be used within a certain temperature range.
The contact mode of the temperature sensor and the measured medium is divided into two categories: contact type and non-contact type. The contact type temperature sensor needs to maintain thermal contact with the measured medium, so that the two are fully heat exchanged to reach the same temperature. This type of sensors are mainly resistive, thermocouple, PN junction temperature sensors. The non-contact temperature sensor does not need to be in contact with the measured medium, but passes through the measured heat radiation of the medium or convection to the temperature sensor to achieve the purpose of temperature measurement. This type of sensor mainly has an infrared temperature sensor. The main feature of this temperature measurement method is that it can measure the temperature of moving substances (such as the temperature of the bearing of a slow-moving train, the temperature of a rotating cement kiln) and objects with a small heat capacity (such as temperature distribution in integrated circuits).