What do fuses do?

Answer 1

Structure and use of a fuse:

A fuse contains of a metal contact cap,glass casing,thin metal wire with a low melting point.When the electric appliances is faluty,the excess electric current will flow through the crcuit.Owing to the heating effect of elecric current,a large amount of heat will be produced.The circuit may thus occured a fire.The installation of fuse can stop excessive electric current.the low melting point thin wire in the fuse will melt and break the circuit in order to protect the electric appliances and prevent a fire.But fuse is quite unconvenient that after it's bruned out,you need to replace a new one.

fuse rating:

fuse rating refers to the amount of electric current that can flow through the fuse without melting the thin metal wire.The higher rating can provide larger electric current.We should choose a greater ampere fuse than the electric appliances in order to prevent the breaking of circuit when electric appliances are working normally.

The similar appliances:Circuit Breaker

The use of a circuit breaker is similar to a fuse.When an electric current increases suddening and exceeds the circuit breaker's raging,the circuit breaker will turn to"OFF" switch automatically and break the circuit in order to protect the electric appliances and prevent a fire.It's more convenient than a fuse cause you only need to turn to"ON"switch when reconnected.