A temperature sensor is a sensor that can sense the temperature and convert it into an output signal. Temperature sensor is the core component of temperature measuring instrument and meter. According to the measurement method can be divided into two types of contact temperature sensor and non-contact temperature sensor, according to the characteristics of materials and electronic components are divided into two types of thermal resistance and thermocouple.
1 contact type temperature sensor
The detecting element of the contact type temperature sensor can be in good contact with the measured object. The heat balance state is achieved by conduction or convection, so that the display value of the thermometer can directly indicate the temperature of the measured object.
2 non contact type temperature sensor
Non contact type temperature sensor sensitive element and the object to be tested are not in contact with each other, this sensor generally used for the surface temperature of the object of measurement of moving objects and small target and heat capacity and temperature change quickly, can also be used for the measurement of the temperature field of the temperature distribution.
3 thermal resistance temperature sensor
Thermal resistance temperature sensor is using conductor or semiconductor resistance value varies with temperature change and change principle of temperature sensor. For different conductor (semiconductor), the temperature changes at one time, the resistance value is different, and the resistance value can be directly used as the output signal.
4 thermocouple sensor
Thermocouple is by two different components of the conductor joined the loop, when the bonding temperature and in the loop will produce thermoelectric EMFs. This phenomenon is called thermoelectric effect, the electromotive force is called the thermal emf. Which directly used for measuring the temperature of a medium is called the measuring end and the other end is called terminal compensation; compensation end and display instrument is connected to the display instrument produced by thermocouple thermoelectric EMFs are pointed out. Thermocouples made from different materials are used in different temperature ranges, and their sensitivities are not the same. The metal material of the thermocouple must have very good ductility, so the thermocouple temperature measuring element has a very fast response speed, can measure the process of rapid change of temperature.
