PTC is stand for Polymeric Positive Temperature Coefficient, it is a kind of semiconductor function ceramic with postive temperature coefficient. This component can protect the electric circuit when the current surge is oversized and the temperature is very high., we can connect them in series in the electric circuit.In the normal condition, its resistance is very small, so is the loss. It does not affect the normal work of the electric circuit; But if there happened to be the overflow current (e.g.,short circuit), its resistance will elevates rapidly along with the temperature , so as to limit current, avoiding to damage primary devices in electric circuit. After trouble shooting, the PTC components temperature will drop automatically, restoring to the low resistivity condition, therefore the PTC component is called the Recoverable Fuse.