How Does the Resettable Fuse Work

How It Works

Our resettable fuses are designed band made of patented novel polymeric PTC material in thin chip form. With electrodes and leads attached on both sides, it is placed in series to protect a circuit. At “normal operating condition” the device remains at an extremely low resistance (milli-ohms) and allows the electrical current to flow through it without any restriction. When over-current conditions occur, the polymetic PTC material heats up and its resistance increases sharply. Such a sharp resistance increase (to an insulated status) cuts off the current in the circuit, and consequently protects the element and device in the circuit. Upon fault current being removed, the resettable fuse cools down and its resistance drops to the original extremely low value. The resettable fuse is “reset” and allows the current flow through the circuit again.