Thermistor

A thermistor is a type of resistor used to measure temperature changes, relying on the change in its resistance with changing temperature.

Related Topics:
Resistor - Temperature - Resistance

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Thermistor is a portmanteau word from the words thermal and resistor.

Related Topics:
Portmanteau word - Thermal - Resistor

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If we assume that the relationship between resistance and temperature is linear (i.e. we make a first-order approximation), then we can say that:

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:Delta R=kDelta T

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where

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:Delta R = change in resistance

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:Delta T = change in temperature

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:k = first-order temperature coefficient of resistance

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Thermistors can be classified into two types depending on the sign of k. If k is positive, the resistance increases with increasing temperature, and the device is called a positive temperature coefficient (PTC) thermistor, posistor or sensistor. If k is negative, the resistance decreases with increasing temperature, and the device is called a negative temperature coefficient (NTC) thermistor. Resistors that are not thermistors are designed to have the smallest possible k, so that their resistance remains almost constant over a wide temperature range.

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