1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Dynamo lamp

  1. Aug 15, 2008 #1

    I have one question. How the circuit of the dynamo light of bicycle is closed? Isn't the coil got two wires, one from the start, and one from the end.

    Thank you.


    Here is one picture:

    http://www.windpower.org/kres/dynbde04.gif [Broken]
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Aug 15, 2008 #2


    User Avatar
    Science Advisor

    The circuit is completed through the bike frame. When you attach the lamp and the generator you'll notice they both include a sharp "pointy" screw designed to penetrate the paintwork and make solid electrical connection to the metal frame.
  4. Aug 15, 2008 #3
    And what happens with the other end of the coil?
  5. Aug 15, 2008 #4


    User Avatar
    Gold Member

    The other end of the coil is grounded to the body of its housing, and the circuit uses the metal frame as a return path to the grounded body of the lamp housing.
  6. Oct 2, 2008 #5
    what is the maximum of a dynamo energy production.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook