Newbie question about PWM led dimmer

Discussion in 'General Electronics Chat' started by denpo, Dec 9, 2012.

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  1. denpo

    Thread Starter New Member

    Aug 17, 2010
    Hi AAC people!
    I'm working on a car restoration project, and I want to convert my interior lighting to led, but I want to retain dimming capacities, so I bought one of those sub-10$ ebay led dimmer in the hope it would fit the bill.
    It doesn't. The design it putting the switching transistor on the negative side of the led serie, the positive side is directly connected to the source's positive post. Just like most of led dimming schematic propose.

    Even will my little understanding of electricity, I can see I couldn't use this device in my existing harness and using car's ground. I would have to wire the + and - down to each led. Not practical.
    I tried to tweak the board to connect the led after the transistor, and of course it didn't work. :confused:
    Here stops my little undersanding of electronic principles :(

    So here's my question, could I modify my existing board to work the way I intent to or do I have to design a new design from scratch, based on schematic like this one :

    Thanks in advance.

    Note: for those here who are into car, here's my resto thread
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    Last edited by a moderator: Dec 9, 2012
  3. Wendy


    Mar 24, 2008
    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Chapter 6, as seen here:

    This can be found in our Terms of Service (ToS)

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    Another good forum that shares many of the same membership is . Good luck.
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