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Homework Help: Building Faraday Flashlight Help

  1. Nov 20, 2008 #1
    1. The problem statement, all variables and given/known data
    I need to build a faraday flashlight and I have two problems.

    2. Relevant equations
    (1) When I use a 12V DC motor connected in parallel to a capacitor (16V 2200uf) and then to an LED assembly, I can't get the capacitor to charge. (2) If I wanted to use a magnet and coils connected to a wave bridge rectifier and then to a capacitor and LED, how would I calculate the amount of Voltage produces by moving the magnet?

    3. The attempt at a solution
    I've already built a flashlight with the DC motor, it is able to turn on the LED but the capacitor just does not charge. I've put in a switch between the capacitor and LED and all I can get it to do is light up when I'm turning the motor and the switch is on; when the switch is off I turn the motor but when I flip the switch on the LED doesn't light up. Could the problem be that my capacitor is too large?
  2. jcsd
  3. Nov 20, 2008 #2


    User Avatar

    Staff: Mentor

    Can you post a schematic of your circuit?
  4. Nov 20, 2008 #3
  5. May 24, 2009 #4
    I think you can see this http://www.lightflashlights.com/ [Broken]. It's very well. And I think that it's very useful.
    Last edited by a moderator: May 4, 2017
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