A thermistor is a specific type of resistor that uses sensors to help regulate cold and heat. They can do more then simply regulate temperature. They are also used for voltage regulation, volume control, time delays, and circuit protection..
Thermistors are of two opposite fundamental types:
- With NTC thermistors, resistance decreases as temperature rises. An NTC is commonly used as a temperature sensor, or in series with a circuit as an inrush current limiter.
- With PTC thermistors, resistance increases as temperature rises. PTC thermistors are commonly installed in series with a circuit, and used to protect against overcurrent conditions, as resettable fuses.