A thermistor is a type of resistor whose resistance is dependent on temperature, more so than in standard resistors. The word is a portmanteau of thermal and resistor. Thermistors are widely used as inrush current limiter, temperature sensors (Negative Temperature Coefficient or NTC type typically), self-resetting overcurrent protectors, and self-regulating heating elements. (Positive Temperature Coefficient or PTC type typically). Thermistors are of two opposite fundamental types: \n* With NTC, resistance Decreases as temperature rises to protect against inrush overvoltage conditions. Commonly installed series in a circuit. \n* With PTC, resistance Increases as temperature rises to protect against overcurrent conditions. Commonly installed series in a circuit. Thermistors differ from resistance temperature detectors (RTDs) 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 greater precision within a limited temperature range, typically −90 °C to 130 °C.

Read full article on Wikipedia · CC-BY-SA