A new compensation scheme for thermistors and its implementation for response linearization over a wide temperature range

A new four-constant curve fit is proposed for the R-T characteristic of a thermistor. That it provides a better fit than the two-constant law R=Ae^BT/ is demonstrated by taking the examples of two standard commercial thermistors. A simple numerical method is suggested for determining the constants of the new fit. Compared to other empirical relationships, the present equation lends itself to easy hardware linearization. A temperature-to-frequency converter that has been developed employing the proposed fit is described. The converter is free from any error due to thermistor lead resistances, and provides an accuracy better than 0.2 K over a temperature range from 300 K to 390 K