A fuse is a safety device intended to melt when a current exceeding a certain strength passes through a conductor. Thus the fuse protects the conductor from being overheated by excess current. The fuse, which consists of a piece of soft metal, such as an alloy of lead, is soldered to copper terminals, so shaped that they may be clamped.

Fig. 92.   A Transformer.

Fig. 92. - A Transformer.