Resettable (polymeric or positive temperature coefficient -  PTC) fuses are unlike traditional fuses that have to be replaced after a fault condition, this may not be necessary when using resettable fuses. The internal resistance of the component increases in response to an overcurrent or a short-circuit condition, limiting subsequent disturbances. After the fault condition is removed, the device cools and the internal resistance drops to nearly its initial value, permitting normal equipment operation to resume.
Resettable PTCs: Learn more