Make an Electric Bell?

Question

Hey Guys... my physics teacher did a summer class which I wasnt able to attend (Clashed with other classes) and she assigned an assignment to us, how to make an electric bell using magnetism, unfortunately i am not able to understand this concept and was hpoing for you guys to help me out on the procedures and stuff. Thanks in advance!

Answer 1

You need to make an electromagnet using a coil of wire wrapped round a rod of iron or steel (eg. a nail). The electromagnet attracts a steel lever. The lever forms the moving part of a switch, and the switch carries the current to the electromagnet. The lever has to be sprung in such a way that when the electromagnet is not energised, the switch contacts are made.

When you apply a voltage, current flows through the switch and the coil. The lever is attracted towards the electromagnet, which breaks the switch contact. Current stops flowing, and the lever returns to its rest position, that makes the switch contact again..... etc. The lever oscillates back and forward. All you have to do then is attach a clapper to the end of the lever and make it strike a bell.