Slow Blow Fuses

A slow blow fuse is different from a fast acting fuse in its capability to withstand transient pulse currents, i.e., it can withstand the surge current upon power-on/off, thus ensuring the equipment works normally.Therefore, low low fuses are often called time-delay fuses. Slow blow fuses are preferably used in capacitive or sensitive circuits where surges occur upon power-on/off and power input/output,like in case of power Amplifiers 

Fast Blow Fuses

Fast blow Fuses are used in circuits without transient inrush currents. Fast-acting fuse opens on overload and short-circuits very quickly. This type of fuse is not designed to withstand temporary overload currents associated with some electrical loads.These Type of fuses are used to protect sensitive Electonic parts Such as Intergrated Circuits and are found in products such as CDP's and Signal Processors.