The material constant B value of NTC thermistor is a key parameter, which is calculated by measuring the resistance value at two temperatures. The calculation method is:

In the formula, T is the Kelvin temperature, and R1 and R2 are the resistance values measured by the thermistor at temperatures T1 and T2, respectively. In experiments, the two commonly chosen measurement temperatures are 25 and 50 ℃ or 25 and 85 ℃.