Fuse- Defination:

                               Fuse is a device which cuts off the circuit when more than predetermined value current flows ina circuit.

                               The current taken by an electric appliance from mains is limited by its resistance in the circuit. Under normal working conditions the circuit  is within safe limit so the  wires and switches do not become hot. If a fault develops there, it may cause the two conductors to come in direct contact with appliance . At that time the resistance will be of wires only which is very low ( about 0.2 ohms). So a high current will flow through these wirse and switchesand these overheat the conductors and it may set fire to the whole building causing serious damage. So some means are arranged to limit this current. Generally, its is so arranged that part of the circuit consists of a conductor which will melt easily and so break the connection when the curent exceeds the predetermined value. Such a conductor is known as "fuse wire".

                              The materials which can be used in fuse are tin, lead, zinc, silver, antimony, copper, aluminium, etc.,

Copper or lead, tin alloys are mostly used in ordinary fuse wire.

                              There a few types of fuses n they are as follows: