A thermistor is a type of resistor whose resistance varies significantly (more than in standard resistors) with temperature. The word is a pormantaeu of thermal and resistor. Thermistors are widely used as inrush current limiters, temperature , self-resetting overcurrent protectors, and self-regulating heating elements.
Thermistors differ from resistance temperature detectors (RTD) in that the material used in a thermistor is generally a ceramic or polymer, while RTDs use pure metals. The temperature response is also different; RTDs are useful over larger temperature ranges, while thermistors typically achieve a higher precision within a limited temperature range [usually −90 °C to 130 °C].
Example Thermometrics Thermistors: