Thermistors are semiconductor resistors that are temperature-dependent. They have a strongly negative temperature coefficient. Because of this, they are also called NTC resistors (NTC = negative temperature coefficient). NCT resistors reduce their resistance value as temperature increases, conducting better. As the temperature drops, the resistance value increases and they conduct more poorly. Since the resistance values are temperature dependent, they are not calculated. They are read off from the characteristic curves on the data sheets.
