The thermistor is a type of sensitive component and is divided into a positive temperature coefficient thermistor (PTC) and a negative temperature coefficient thermistor (NTC) according to the temperature coefficient. Typical characteristics of thermistors are temperature sensitive and exhibit different resistance values at different temperatures. The positive temperature coefficient thermistor (PTC) has a higher resistance value at higher temperatures, and the lower the resistance value of the negative temperature coefficient thermistor (NTC) at higher temperatures, they belong to the semiconductor device.
A chip ntc thermistor is a type of thermal resistor, so the principle is that temperature causes a change in resistance. But now the thermal resistance is generally industrialized, basically refers to PT100, CU50 and other common thermal resistance. The difference between the two is: general thermal resistance refers to metal thermal resistance (PT100), etc., chip ntc thermistor refers to semiconductor thermal resistance due to The temperature coefficient of the semiconductor thermal resistance is 10 to 100 times larger than that of the metal, and the temperature change of 10-6 ° C can be detected, and the resistance value can be arbitrarily selected between 0.1 and 100 kΩ. So called the thermistor.
However, the curve of the chip ntc thermistor resistance with temperature is nonlinear, and the linearity of each of the same models is different, and the temperature range is relatively small. Therefore, the industry generally uses metal thermal resistance ~ which is what we usually call the thermal resistance. The chip ntc thermistor is typically used in a circuit board, such as what is commonly said to be similar to a fuse. It can be used as a protector because its resistance varies greatly with temperature. Of course, this is only one aspect. It has many uses. For example, the cold junction temperature compensation of a thermocouple is compensated by a thermistor. In addition, since the relationship between the resistance and the temperature is nonlinear, the consistency of the components is poor, and there is no standard signal like the thermal chip ntc thermistor.
The characteristics of the thermistor:
1.The sensitivity is higher, the temperature coefficient of resistance is 10~100 times larger than that of metal, and the temperature change of 10-6 °C can be detected;
2.Wide operating temperature range, room temperature device is suitable for -55 ° C ~ 315 ° C, high temperature device temperature is higher than 315 ° C (currently up to 2000 ° C), low temperature device is suitable for -273 ° C ~ -55 ° C;
3. Small in size, able to measure the temperature of the voids, cavities and blood vessels in the body that other thermometers cannot measure;
4 .Easy to use, the resistance value can be arbitrarily selected between 0.1 ~ 100kΩ;
5 .Easy to process into a complex shape, can be mass-produced;
6 .Good stability, strong overload capability