Thermistor Thermometer Bridge: Linearity and Sensitivity for a Range of Temperature

Abstract

The balance point of a Wheatstone bridge with a slide wire for ratio arms is a nearly linear function of the temperature of a thermistor in a third arm, the maximum errors of a linear calibration are made equal and proportional to the cube of the temperature range, and the off‐balance sensitivity is nearly constant for a considerable temperature range. For a small thermistor with a 2000‐ohm resistance at 25°C, the slide position of a linear potentiometer is proportional to the thermistor temperature ±0.5°C, and the deflection of a taut suspension pointer galvanometer is 20±1 mm/°C over the temperature range from 0°C to 50°C with a maximum thermistor temperature rise of 0.05°C in still air.