Electromagnetic Doorbell

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The electromagnetic doorbell is an example of a self-interrupting electrical circuit. Pushing the bell button closes the switch (S) and connects the electromagnetic coil (M) to the battery (B). The activated electromagnet then attracts the clapper (A), which hits the bell but also interrupts the electric circuit at the contact (C). The magnet is then cut off and the clapper is released, closing the circuit…. This process is repeated as long as the button is depressed.


Reset the animation before pushing the button to ring the bell and show its operation. Adjust the ringing frequency, volume, and note of the ring as desired.

American scientist Joseph Henry invented the electromagnetic doorbell around 1831 [1].

The operation of the electric doorbell is explained in [2].


Contributed by: Erik Mahieu (April 2012)
Open content licensed under CC BY-NC-SA




[1] F. P. Bachman, Great Inventors and Their Inventions, Chapel Hill: Yesterday's Classics, 2010 pp. 78–79.

[2] T. Harris. "How Doorbells Work." How Stuff Works. (2011) home.howstuffworks.com/home-improvement/repair/doorbell2.htm.

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