In Electrical Engineering a fuse is an electrical safety device that operates to provide overcurrent protection to an electrical circuit. The fuse is a short piece of metal that is connected in series to the circuit. A fuse melts when excessive current flows through it and thereby breaks the circuit.
The fuse element is usually made of materials that are having low melting point, high conductivity and least deterioration because of oxidation. A fuse connects in series to the circuit that is to be protected.
During its normal operating conditions, the fuse element is at a temperature below its melting point and it continues to carry the normal current without overheating.
When a short-circuit or overload happens the current through the fuse increases beyond its rated value thereby raising the temperature of wire. Due to excessive heat produced by high temperature, the fuse wire melts thereby disconnecting the circuit protected by it.
The fuse possesses inverse time-current characteristics. The time needed to blow out the fuse is inversely linked to the magnitude of excessive current. The greater the current is, the smaller is the time taken by the fuse to blow out.
The figure below displays a 5 A 125 V fuse. Such a fuse finds its applications as in-line fuse for extension cords for lights. Laptop adopter and similar electronic components also use glass fuses for protecting purposes.
Advantages of Fuse
A fuse is an economical power system protection device that requires no maintenance and it possesses an inverse time-current characteristic that makes it suitable for overcurrent protection. See complete list of Top 10 advantages of fuse here
Disadvantages of Fuse
A fuse is a one-time operation device, once it operates, replacement is necessary. The current discrimination is also difficult in case of fuses. Read the complete list of disadvantages here.