The Study of Temperature Calibration Method for NTC Thermistor

NTC thermistor temperature sensor has extensively used in many fields. The biggest disadvantage of it is the low temperature measurement accuracy and poor interchangeability. In order to increase temperature measurement accuracy of NTC thermistor without increasing calibration workload too much, an experimental setup was built to measure the resistance of NTC thermistors at different temperatures. The standard thermostatic bath was used as the temperature source, and the standard platinum resistance thermometer was used as the temperature measuring standard in the experiment. The exponential empirical formula was used as the calibration equation, and four different schemes were developed to obtain the parameters in the exponential empirical formula respectively. The results show that the average error and standard deviation are the lowest in scheme 5 in which the parameter of B in exponential empirical formula is calculated by the experimental data conducted at the upper and lower limits of the temperature range. The calibration method in scheme 5 can greatly improve temperature measurement accuracy of NTC thermistor, and does not increase the calibration workload too much, which has a strong engineering application value.