Question

Draw a neat and labelled diagram of an electric bell and describe its working.

Answer 1

$$\text{Working}$$

• When a push button fitted in a battery is pressed, the current flows through the contact points via an electromagnet.
• The U shaped electromagnet is magnetized and it attracts the armature towards it.
• The hammer fitted with strip gives a strike on the gong producing sound.
• The moment this happens, contact of the attached spring with screw is broken, i.e. the circuit is broken.
• As a result, current stops flowing and the electromagnet is demagnetized.
• Due to this action of the spring, armature comes to its previous position, i.e. comes in contact with the screw and the circuit is again completed.
• Each approach of the armature or strip causes the hammer to strike the gong.
• Thus, the same process is repeated many times and the bell goes on ringing.