热敏电阻是热敏感的电阻器，其主要功能将在体温发生相应变化时表现出较大，可预测和精确的电阻变化。当受到体温升高和正温系数（PTC）热敏电阻时，负温度系数（NTC）热敏电阻显示出电阻的降低，当受到体温升高时，电阻会增加。美国传感器Corp.®于2017年被Littelfuse收购，可产生能够在-100°的温度范围内运行到 +600°Fahrenheit的热敏电阻。由于其非常可预测的特性及其出色的长期稳定性，因此热敏电阻通常被认为是许多应用包括温度测量和控制的最有利传感器。
Since the negative temperature coefficient of silver sulphide was first observed by Michael Faraday in 1833, there has been a continual improvement in thermistor technology. The most important characteristic of a thermistor is, without question, its extremely high temperature coefficient of resistance. Modern thermistor technology results in the production of devices with extremely precise resistance versus temperature characteristics, making them the most advantageous sensor for a wide variety of applications.
由于温度变化的相应温度变化，热敏电阻的电阻变化是否是由于周围环境的传导或辐射而变化的，还是由于设备内的功率耗散而导致的“自加热”。
When a thermistor is used in a circuit where the power dissipated within the device is not sufficient to cause "self heating", the thermistor's body temperature will follow that of the environment. Thermistors are not "self heated" for use in applications such as temperature measurement, temperature control or temperature compensation.
When a thermistor is used in a circuit where the power dissipated within the device is sufficient to cause "self heating", the thermistor's body temperature will be dependent upon the thermal conductivity of its environment as well as its temperature. Thermistors are "self heated" for use in application such as liquid level detection, air flow detection and thermal conductivity measurement.