Temperature transducer A sensor that senses a temperature and converts it into an available output signal. Temperature sensor is the core of temperature measurement instruments, a wide variety. According to the measurement method can be divided into contact and non-contact two categories, according to the sensor material and electronic components are divided into two types of thermal resistance and thermocouple.
Contact the temperature sensor detection part and the measured object has a good contact, also known as thermometer.
The thermometer achieves heat balance by conduction or convection, so that the thermometer's indication can directly represent the temperature of the object to be measured.
General measurement accuracy is higher. In a certain temperature range, the thermometer can also measure the temperature distribution within the object. But for the movement of small objects or small heat capacity will produce a large measurement error, commonly used thermometer with bimetallic thermometer, glass liquid thermometer, pressure thermometer, resistance thermometer, thermistor and thermocouple and so on. They are widely used in industrial, agricultural, commercial and other sectors. People often use these thermometers in their daily lives. With the low temperature technology in the defense engineering, space technology, metallurgy, electronics, food, medicine and petrochemical and other departments of the extensive application and superconducting technology research, measuring the temperature below 120K low temperature thermometer has been developed, such as low temperature gas thermometer, Pressure thermometer, acoustic thermometer, paramagnetic thermometer, quantum thermometer, low temperature thermal resistance and low temperature thermocouple. Low temperature thermometer requires temperature sensor components small size, high accuracy, reproducibility and stability. The use of porous high silica glass carburizing sintered carburizing glass thermal resistance is a low temperature thermometer temperature sensor can be used to measure the temperature range of 1.6 ~ 300K.
Its sensitive components and the measured object is not in contact with each other, also known as non-contact thermometer. This instrument can be used to measure the surface temperature of moving objects, small targets and heat capacity or temperature changes rapidly (transient) objects, and can also be used to measure the temperature distribution of the temperature field.
The most commonly used non-contact thermometer based on the basic law of blackbody radiation, known as radiation thermometer.
Radiation temperature method includes brightness method (see optical pyrometer), radiation method (see radiation pyrometer) and colorimetric method (see colorimetric thermometer). All kinds of radiation temperature measurement method can only measure the corresponding luminous temperature, radiation temperature or color temperature. Only the black body (absorb all the radiation does not reflect the light of the object) measured temperature is the real temperature. To determine the true temperature of the object, it is necessary to modify the surface emissivity of the material. The surface emissivity of the material depends not only on the temperature and wavelength, but also on the surface state, coating and microstructure, etc., it is difficult to accurately measure.