Page 891 - Basic Electrical Engineering

Figure 12.11 (a), (b), (c) show three types of thermistors; (d) shows use of a thermistor in a
wheatstone bridge for measurement of temperature

The voltage generated can be used to make digital output or analog
deflection depending upon the arrangement. If calibrated, the output will be a
measure of the variation in temperature.

The sensitivity of a thermistor is expressed in terms of variation of
resistance per degree change in temperature. High sensitivity of thermistors

together with their initial high value of resistance make them suitable for
measurement of temperature accurately. They are, therefore, suitable for
precision temperature measurement and its control. Thermistors can be used

to measure minute change of temperature variation, as low as 0.005°C.
Since the resistance versus temperature characteristic of thermistors are

non linear (resistance decreases non linearly with temperature rise), they can