Question

Give the symbol of an electric fuse used in circuit diagrams.

Answer 1

Hint: An electrical fuse limits the current flowing in a circuit when there is an overloading or a sudden high fluctuation in voltage. The overloading or sudden high fluctuations will cause the circuit to heat up and can even lead to a fire. Given below is an image of an electric fuse in a casing.

Complete answer:
Sketch the symbol of the electric fuse used in a circuit diagram and try to briefly explain its working.
The symbols of an electric fuse are sketched below.

While connecting an electric fuse in a circuit diagram, any one of the three symbols can be used.
When the current in the circuit reaches its threshold or in other words, when the current is beyond the circuit’s bearing limit, the circuit will overheat. This then causes the fuse wire to melt and break the flow of the current in the circuit. The circuit gets thus protected from damage.

Additional information: Connecting many electrical appliances of high power rating (iron box, heater) at the same time will lead to excess current to flow through the circuit. These appliances draw huge amounts of current from the circuit which then give rise to overloading.
A short circuit is another scenario where an excess current suddenly passes through the circuit. A short circuit is when a positive and a negative wire come in direct contact with each.

Note: The electric fuse will always be connected in series with the appliance. The series connection ensures that during overloading, the whole current flows through the fuse wire. The electric fuse consists of a wire made of a material having a low melting point. So, the overheating of the circuit will cause the fuse wire to melt easily and stop the current flow.