Electrical devices can experience potentially damaging surges and overcurrent conditions from short circuits and overload. When excess current flows into a circuit, sensitive electronic devices can be damaged or destroyed, as shown here in this example circuit. Such events also can create an open circuit in the thermal switches of expensive transformers. One step in protecting a circuit is to incorporate a fusible resistor. The fusing characteristics of the FW Series allow the resistor to act like a fuse and open, thus helping to block potentially damaging surges.