What is thermistors? 

Basically thermistor is also called thermal resistor. And thermistors work on the principle that as the temperature of a resistive material changes, its resistance will also change. Although the resistance of all resistors changes slightly with the change in temperature. But thermistors are designed to be sensitive to temperature changes. They are widely used in temperature measurement because they are cheap and robust methods of temperature measurement. The thermistor has a temperature measurement range of -55°C to +115°C.