5K40.80 Hand Crank Flashlight

Concepts

Electromagnetic induction, conservation of energy, Faraday's law

Overview

A magnet mounted on a flywheel spins when the handle is squeezed, changing the magnetic flux and generating an EMF that illuminates a light bulb.

Details

Equipment

  • [1] Squeeze flashlight

Important Notes

  • For large lectures, a camera would be useful for showing the internal structure of the hand crank flashlight.

Script

  1. For a large lecture, dim the lights.
  2. Squeeze the handle repeatedly until light bulb turns on.

 

Additional Resources

References

  • PIRA 5K40.80

Disclaimer

  • Don't attempt this at home!

Last revised

  • 2023

Technicals

  • Original construction: purchased. The flashlight contains a coil and a rotating magnet.

Related AV

Related demos

  • Forever Flashlight

If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.