Advantage of Thermistor Thermistors generally consist of semiconductor materials. Most thermistors in use nowadays are characterized by a negative temperature coefficient, meaning that their resistance decreases with increasing temperature. Temperature coefficient change can be as high as several percentage factors per degree Celsius. Consequently, thermistors are able to detect even the smallest temperature changes, which would otherwise go undetected with a reverse temperature detectors or thermocouple. The price to be paid for this high sensitivity is loss of linearity. Thermistor behavior is extremely non-linear and as such, thermistor readings are strongly dependent on process parameters. Consequently, thermistors are not as widely standardized as RTDs or thermocouples. Positive temperature coefficient thermistors (PTC) thermistors can be used as current- limiting devices for circuit protection, as replacements for fuses. Current through the device causes a small amount of resistive heating. If the current is large enough to generate more heat than the device can lose to its surroundings, the device heats up, causing its resistance to increase, and therefore causing even more heating. This creates a self-reinforcing effect that drives the resistance upwards, reducing the current and voltage available to the device. Negative temperature coefficient (NTC) thermistors are used as resistance thermometers in low-temperature measurements of the order of 10 K. NTC thermistors can be used as inrush- current limiting devices in power supply circuits. They present a higher resistance initially which prevents large currents from flowing at turn-on, and then heat up and become much lower resistance to allow higher current flow during normal operation. These thermistors are usually much larger than measuring type thermistors, and are purpose designed for this application. Thermistors are also commonly used in modern digital thermostats and to monitor the temperature of battery packs while charging.