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Posted by rajascientist Tuesday, September 1, 2009

You might have all came across many electric bells using electromagnet ,this is yet another one with slight modification , a home made electric bell.

Materials Required:

  1. Gong ( toy car )
  2. Hammer (battery cover sheet)
  3. Electromagnet ( Picture tube coil)
  4. 9 V battery
  5. Simple Switch Mechanism.(hanging wire)
  6. Pole Supporting Hammer ( pen refill)


When electric current passes through a coil wound on a soft iron core ,iron acts as a temporary magnet. It acts as a magnet until current passes through it. I got this electromagnet from junk TV picture tube, works perfectly.

More the number of turns ,more the applied voltage the strength of electromagnet will increase.

Gong :

Look for it in some toy cars ,or else take some tensile metal .


Do it yourself. I made one out of a battery cover metal sheet.

Simple Switch Mechanism:

It is the switch mechanism which varies from bell to bell. It depends upon creativity of creator. Many types mechanism are available. I have used hanging type switch. Nothing but a simple strip of wire hanging down touching the hammer.

Whenever the hammer is pulled and released , the circuit opens and closes.


A small pole is erected near the electromagnet , bearing spring and holding hammer. I used a pen refill as a pole and a spring around the refill. Which gives the necessary tension to the hammer.

This is how it works . The speed of the hammer can be increased by increasing the power of electromagnet .


  1. Kotag Says:
  2. how much rolls the core??

  3. Normally 200 to 300 turns ll do...It depends on the strength of magnet you require and the voltage you use.

  4. wats d hammer..


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