PPTC(Polyer Positive Temperature Coefficent)

AOLITTEL is one of the famous China PPTC(Polyer Positive Temperature Coefficent) manufacturers and suppliers. Our factory specializes in manufacturing of PPTC(Polyer Positive Temperature Coefficent).

The main encapsulation of SMD self recovery fuses are: 0805, 0603, 1206, 1812, 2920, and their working principle is:

The self recovery fuse is composed of specially treated polymer resin and conductive particles (Carbon Black) distributed inside. Under normal operation, the polymer resin tightly binds conductive particles outside the crystalline structure, forming a chain like conductive electrical pathway. At this time, the recoverable fuse is in a low resistance state (a), and the heat generated by the current flowing through the self recovering fuse on the circuit is small and does not change the crystal structure. When a circuit experiences a short circuit or overload, the heat generated by the large current flowing through the self recovery fuse causes the polymer resin to melt, rapidly increase in volume, and form a high resistance state (b). The working current rapidly decreases, thereby limiting and protecting the circuit. After the fault is eliminated, PTC can restore the fuse to cool and crystallize again, shrink the volume, and the conductive particles form a conductive path again. The self restoring fuse returns to a low resistance state, thus completing the protection of the circuit without the need for manual replacement.