2. Circuit connections

A simple circuit is constructed where the bulb glows when the switch is turned 'ON', and when the switch is turned 'OFF', the bulb stops glowing. The circuit arrangement can be drawn using the symbols of electric components. An electric circuit is generally represented by a circuit diagram to make it simple.

 

Circuit diagram showing the switch in ON state

 

Circuit diagram showing the switch in OFF state

 

The symbols of the cell, switch, and a lamp or bulb can be drawn anywhere in the circuit.

The bulb is made up of a glass that is fixed on a metallic base. Filament is made of thin tungsten wire that gives light when electricity flows through it. It is placed between two thick connecting wires which act as a support to the filament.

 

 

When the tip of the base of the bulb is in contact with the positive terminal of the cell, the bulb glows. When the bulb is taken away from the terminal of the electric cell, the bulb does not glow. A bulb becomes fused if there is a break in the filament of an electric bulb. Due to the break in the path of the current, the fused bulb does not glow.

 

NOTE: Thomas Alva Edison invented electric bulbs. He has invented around \(1300\) products which includes gramophone, the motion picture camera and the carbon transmitter.

An electric circuit can made using a single cell and a bulb. The bulb does not glow when the switch is kept in the 'OFF' state, and hence no heat is produced. When the switch is turned 'ON', the bulb glows.