The fusing performance of the different FW models is illustrated in the series data sheet. The curves are shown here for each power rating of the fusible resistor. Bourns® FW Series performs like a standard fuse, and performance is measured in terms of power and time. Fusing time accelerates with increased power due to the heating effects of I2R. The fuse typically is applied at 120 VAC or 240 VAC for 1-5 W models, and 240 VAC for the 7 W model.