A Study of Point Selection Strategies for Fitting Negative Temperature Coefficient Thermistors

Negative temperature coefficient thermistors have a high degree of nonlinearity in the resistance–temperature curve, which needs to be fitted with equations in practical applications. The effects of the number of selected points and the way of point selection on the fitting results of different equations in the range of (−50 to 100) °C are explored, and the results show that selecting 11 fitting points with the temperature/resistance combination method can improve the accuracy of S–H fitting, which is suitable for fields with lower precision requirements. For high-precision measurements, the Hoge-2 and Hoge-3 equations should be used with a temperature uniformity point selection method, and the optimal number of fitting points is 11 and 6, respectively.