A thermistor is a temperature dependent resistor. It is made from a semiconductor material that has a negative temperature coefficient. As the temperature of the thermistor increases the resistance decreases.Thermistors are used in temperature sensing circuits for simple thermometers, thermostats and to monitor the temperature in a wide range of electrical devices such as engines, toasters, kettles, fridges and freezers.Electrical devices such as smart phones and computer will be powered down before overheating.IV characteristics of thermistors: