Thermistors are thermal sensitive resistors whose primary function are to exhibit a change in electrical resistance with changes in temperature.
NTC (Negative Temperature Coefficient) thermistors
- zero-powered resistance (no power dissipated)
- its resistance decreases with an increase in temperature
The resistance of an NTC is sensitive to temperature changes in a generally linear manner. It is normal to choose NTC thermistors when a continuous linear change of resistance with temperature is required, such as temperature compensation, temperature control systems and inrush current limiting.
PTC (Positive Temperature Coefficient) thermistors
- zero-powered resistance (no power dissipated)
- its resistance increases with an increase in temperature
PTC exhibits only a slight change of resistance with temperature until the “switching point” is reached, at which point an increase of several orders of magnitude in resistance occurs. It is normal to choose a PTC thermistor for self reset-capable fuses and heater applications.