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Thermal resistance and thermocouple temperature sensor standard

release time:2018-6-12  Views:642

Temperature sensor, now we are more familiar with it. According to the characteristics of sensor materials and electronic components, temperature sensors mainly include thermocouples and thermal resistance temperature sensors. However, when used, the use of thermal resistance and thermocouple temperature sensors meets the requirements for the accuracy of process control measurement signals.
Since pure metal has the greatest impedance change, especially a very pure precious metal. Resistive temperature sensors use the resistance value to detect temperature. The positive temperature coefficient thermistor's resistance value is proportional to the temperature, while the negative temperature coefficient thermistor is just the opposite.
If the resistance is linear with temperature, the temperature value can be calculated by a polynomial. In general, resistance thermometers have a measurement range of -250°C to 1000°C. This type of sensor includes standardized sensors made of platinum, such as: Pt100, 100Ω at 0°C. In high-precision measurement, they can be applied to a variety of operating conditions up to 850°C. Thermocouples, though not as accurate as thermal resistors, have faster response times.
A thermocouple temperature sensor can be composed of two different metals or semiconductors connected to each other. When there is a temperature difference between the two metals, a pressure drop will occur at the junction. This phenomenon is also called the Seebeck effect. The thermal voltage of the metal is related to the temperature and generates a few microvolts per Kelvin.
In fact, this measurement principle measures the temperature difference between the hot and cold ends. If you want to determine the temperature of the hot end, you must know the temperature of the cold end. vice versa. In practice, people usually use other temperature sensors to measure the temperature of the cold end. The hot end temperature can be pushed down by the thermal voltage. Thermocouple sensors are commonly used to measure temperatures in excess of 1000°C. Its accuracy depends on the precise measurement of the temperature at the junction.