Electrical Bell:

1.An electromagnet, which is made by winding insulated copper wire on a soft iron core.

2.An armature which is soft iron strip with spring.

3.A soft iron with a small hammer at one end which strikes the gong and form sound.

4.Electric circuit having of

a) Push button                                  b) A battery of potential difference V

c) Contact adjusting screw

Working:

1.When push is pressed, the circuit is finished and the armature is attracted towards the electro magnet.

2.With forward movement of armature, the spring is detached from the screw, the circuit is detached and electromagnet is demagnetized.