Book Analog Interfacing to Embedded Microprocessors
Temperature Sensors
Temperature is one of the most common real-world characteristics that needs
to be measured. Many industrial processes, from steel manufacturing to semi-
conductor fabrication, depend on temperature. Some electronics products
need to measure their own temperature, such as a computer that monitors
the temperature of the CPU or a motor controller that must know the tem-
perature of the power driver IC.
Thermistors
A thermistor is a temperature-sensitive resistor. Most thermistors have a
negative temperature coefficient (NTC), meaning the resistance goes up as
temperature goes down. Of all passive temperature measurement sensors,
thermistors have the highest sensitivity (resistance change per degree of tem-
perature change). Thermistors do not have a linear temperature/resistance
curve.
Thermistor characteristics are dependent on the manufacturing process
and materials used. Often, many thermistors in a family will have similar char-
acteristics and identical curves
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