An NTC thermistor, or negative temperature coefficient thermistor, is a sensor resistor whose resistance value decreases with increasing temperature. It is usually made by firing metal oxides such as manganese (Mn), nickel (Ni), and cobalt (CO), and belongs to semiconductor devices. NTC thermistors have a wide operating temperature range, ranging from -40 to 125 and -273 to 2000.
The resistance of an NTC (negative temperature coefficient) thermistor decreases as the temperature increases. The formula for calculating the resistance value is as follows:
Equation 1: 1 t = a + b * ln(r r0) + c * ln(r r0)) 3
t: Temperature in Kelvin
r: The resistance value of the NTC resistor in ohms
R0: The value of the resistance of the NTC resistor at a reference temperature (in ohms).
a, b, c: constants.
Equation 2: rt = rref * exp(b * 1 tt - 1 tref)).
RT: The resistance of the thermistor at the temperature tt.
rref: The nominal resistance of the thermistor at the temperature tref.
B: The B value of the thermistor, which is related to the material and manufacturing process of the thermistor.
tt: The temperature of the thermistor (in Kelvin).
TREF: The standard temperature of a thermistor (usually 25 degrees Celsius).
Equation 3: rt=r0*(1+ *t-t0))).
RT: The resistance value at the temperature t.
r0: The resistance value at the reference temperature t0 (usually 25).
Linear temperature coefficient.
However, different formulas apply to different temperature ranges and situations. When using it, it is necessary to select the appropriate formula according to the specific needs and conditions, and ensure the accuracy of the parameters.