NTC is the abbreviation of Negative Temperature Coefficient, which means negative temperature coefficient. NTC thermistor is a negative temperature coefficient thermistor. The simple points are that the temperature increases, the resistance decreases, the temperature decreases, and the resistance increases.
NTC thermistors are made of manganese, cobalt, nickel, copper and other metal oxides as the main materials. These metal oxide materials have semiconductor properties because they are completely similar to germanium, silicon and other semiconductor materials in the way of conducting. When the temperature is low, the number of carriers (electrons and holes) of these oxide materials is small, so their resistance values are high; With the increase of temperature, the number of carriers increases, so the resistance value decreases. The output resistance (R) of NTC thermistor temperature sensor varies from 100 Ω to 2000000 Ω at room temperature, and the temperature coefficient (B) ranges from 2000 to 6500 (unit: K).
What are the two most important parameters in the selection of NTC thermistor, R value and B value?
For example: R25=10.0k Ω± 1.0%
It means that at 25 ℃, the output resistance of NTC thermistor is 10K Ω, with an accuracy of ± 1%
B value is a temperature coefficient value of NTC thermistor (related to material ratio). The larger the B value is, the steeper the temperature change curve is, and vice versa. Its unit is K, and the formula is as follows:
For example: B25/50=3435K ± 1.0%
B value at T1=25 ℃, T2=50 ℃, accuracy 1%
NTC thermistor temperature sensor is generally cheap, with low temperature measurement accuracy. The detection range is about - 40 ℃~300 ℃. It can be widely used in occasions where the accuracy and temperature range requirements are not high, such as temperature measurement, temperature control, temperature compensation, etc.