Write a short note on electric bell.

A bell work on the principle of electromagnet. That is conversion of a conductor wire into magnet when electricity is passed through it. All bell whether they are advance or old they have this common principle.

Bell consist of following parts:

•Electromagnet

•Soft iron strip(hammer)

•Contact Screw

•Bell(metallic gong)

Working of bell:

•In its rest position the hammer is held away from the bell by its springy arm. When an electric current is enabled to pass through the winding of the electromagnet by closing of the switch.

•It creates a magnetic field from electromagnet that attracts the iron arm of the hammer, pulling it over to give the bell a tap. (Iron arm is just in front of the electromagnet in the picture)

•But this opens the circuit from the contact screw attached to the hammer arm, interrupting the current to the electromagnet.

•Thus, the magnetic field of the electromagnet collapses, and the hammer springs away from the bell.

•This closes the circuit again from contact screw, allowing the current to flow to the electromagnet again, so again the magnet pulls the hammer over to strike the bell.

•This cycle repeats rapidly, many times per second, resulting in a continuous ringing.