What is fuse? What is its need?
Fuse is a safety device which is installed in a electric or electronic circuit. It limits maximum current flow in the circuit.
If current flows above the specified limit, it breaks the circuit and ensures safety of the whole circuit. For any circuit fuse is placed at initial point of circuit.
Fuse is made up of naked wire enclosed in non combustible casing. Two terminals joining two ends of this wire are taken out of casing. When current is supplied to circuit it flows from one terminal to fuse wire and then to circuit through other terminal.
In other words fuse is placed in series connection so that it takes whole load of circuit.
Property of Fuse wire is such that if current flows through it more than specified limit it burns out and breaks the circuit. Reason of burning is the resistance of wire against current flow. When current higher than specified flows through it, wire heats above melting point and thus melts called as burning.
Property of fuse wire is very crucial because if it fails to break the circuit at specified current rating it is like not having a fuse at all, also if it is not sustaining the rated current or minor current surges it will break the circuit for no reason and hamper working of device.
Reason why it is needed is because fault like short Circuit, overloading and system failure may occur in any type of device and in such scenario heavy current is drown to circuit and if fuse it not placed in the circuit whole device may burn out or Major failure may occur.
So in order to prevent that from happening fuse is placed. Which is easy to replace and low in cost.