FET Fundamentals Unit 8 – Transducers
Exercise 1 – Thermistor Operation
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to demonstrate the relationship
between thermistor resistance and temperature by using self-heated and externally-heated test
circuits. You will verify your results with a multimeter.
EXERCISE DISCUSSION
- A thermistor is a thermally-sensitive resistor whose primary function is to exhibit a change in
resistance with a change in body temperature. - Thermistors are used for precise temperature detection, measurement, compensation, or
control. - Thermistors are typically nonlinear and have negative temperature coefficients.
- Thermistors are made by heat-treating, under pressure, a mixture of metallic oxides. The
process used is called sintering. - Thermistors are more sensitive than thermometers. Some thermistors show a resistance
change of several thousand ohms per degree of temperature. - Thermistors respond quickly to changes in temperature; therefore they have a fast time
constant. - Thermistors can by used in passive or active circuits