Knowledge: What Is Thermistors?

Thermistors belong to sensitive components, divided into positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC) according to the temperature coefficient. The typical characteristic of thermistors are sensitive to temperature and output different resistance values at different temperatures. Positive temperature coefficient thermistors (PTC) show the larger resistance at higher temperatures, negative temperature coefficient thermistor (NTC) show smaller resistance at higher temperatures, all of which are semiconductor devices.

Features of Thermistors
1. High sensitive, TCR is 10-100 times larger than metal and it can test 6-10℃ temperature shift.
2. Work temperature range is wide, normal temperature resistors are applied to -55℃～315℃, high temperature resistors are applied to 315℃(at present it can be used at temperature of 2000℃), the low temperature resistors are applied to -273℃～-55℃.
3. Small dimension, it can measure temperatures of the voids, cavities and blood vessels in biological body that other thermometers cannot measure.
4. Easy to use, resistance can be 0.1～100kΩ.
5. Easy to process complicate shapes and mass produce.
6. High stability and strong overload capacity.

Materials of Thermistors
Materials of thermistors contain semiconductor, metal and alloy.

Semiconductor material: they have strong TCR and high resistance rate, and the convertor made of this material is very sensitive. It can be used for thermistor thermometer, thermistor switch, etc.

Metal material: high stability and high precision for platinum convertor. Platinum resistor thermometer and copper resistor thermometer, etc.

Alloy material: it has higher resistance rate and resistance is sensitive to temperature, very good to make thermal sensitive convertor. They are widely used for temperature monitor, such as fields of environment monitor, food long-term storage, biological engineering and sophisticated military engineering.