Understand the temperature coefficient and characteristics of the thermistor

I believe everyone knows that the main principle of the thermistor changes according to the temperature change, so the temperature coefficient of the thermistor often needs to be measured.

The thermistor is an element made up of a semiconductor ceramic working body that is very sensitive to temperature. It has a much larger value of the temperature coefficient of resistance than the commonly used metal resistors. According to the temperature coefficient of resistance, the thermistor can be divided into three categories: positive resistance temperature coefficient thermistor; critical resistance temperature coefficient thermistor; common negative resistance temperature coefficient thermistor.

As a temperature sensor, the thermistor has the advantages of low material consumption, low cost, small size, simple structure, large value of temperature coefficient of resistance, etc., and can easily and sensitively measure small temperature changes. China's relevant research institutes have also developed a series of different types of thermistor sensors that can measure temperatures from -260 ° C to 900 ° C, and are widely used in artificial earth satellites and related fields such as aerospace technology, deep sea exploration and scientific research. The thermistor-temperature characteristics are compared to the resistance-temperature characteristics of metals and have three characteristics:

The resistance-temperature characteristics of the thermistor are non-linear (exponentially decreasing), while the resistance-temperature characteristics of the metal are linear. The resistance of the thermistor decreases with increasing temperature, so the temperature coefficient is negative. The temperature coefficient of the metal is positive. The temperature coefficient of the thermistor is about -(30~60)×10-4K-1, and the temperature coefficient of the metal is 14104K (copper). Compared with the temperature coefficient of the thermistor, the temperature coefficient is almost several times larger. Therefore, the resistance of semiconductor resistors to temperature changes is much more sensitive than metal resistance.

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