Explanation

(a) Electric fuse is a type of over current protection device. They are engineered to contribute a negligible amount of extra resistance to the circuits they protect. This is largely accomplished by making the fuse wire as short as possible. Fuses are primarily rated as current amperes. A fuse wire of certain material and gauge will blow at a certain current no matter how long it is. Since, length is not a factor in current rating the shorter it can be made the less resistance it will have end to end.