This thermistor is designed to operate at 250 volts AC mains voltages and is intended for general purpose over-current protection, although it may also be used for over-voltage and direct over-temperature protection. Provided the current passing through the thermistor remains below I(max) the effects of self heating will remain negligible and the resistance of the device will remain low (i.e. approximately at the resistance quoted at 25 Deg C). Under fault conditions the current exceeds I(max) and the thermistor starts to self heat, then the resistance increases until the current passing through the thermistor reduces to I(reset).
