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Designing a regulator?

Discussion in 'General Electronics Discussion' started by KennyMcCormick, Sep 8, 2013.

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  1. KennyMcCormick

    KennyMcCormick

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    Sep 8, 2013
    Hi, I want to power an existing LED array from a wall-wart type adapter. I designed the array for use with 6v lead acid batteries, which are usually around 6.7V fully charged. Is there any good info on how I can design a regulator to get a smooth and constant supply from the nasty, lumpy general purpose wall-warts? I know a 6V adapter can be as few volts out in either direction, and they fluctuate a lot, which is not good for LEDs.
    Where can I find detailed info on how to design a regulator circuit to build into the array?
    I've seen self-contained voltage regulators, but I have never used them, and don't know anything about them. Would I have to do any designing? Does it matter how far above/below the desired output voltage the input is? I'd assume it does, but how much? And what if the input can vary quite a bit?
    As long as the wall wart can easily provide the current required by the array, is this an easy thing to design? Where can I find the maths?

    I'm sure there are units that already have built-in regulation, but I'd like to learn more about this for other projects, plus I like the idea of being able to easily find replacement supplies in any hardware store.
     
  2. davenn

    davenn Moderator

    13,785
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    Sep 5, 2009
    hi there
    welcome to the forums :)

    have a look here in the tutorials section

    cheers
    Dave
     
  3. KennyMcCormick

    KennyMcCormick

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    Sep 8, 2013
    Forget I mentioned LEDs. LED drivers are a pain in the butt on every forum and the subject gets hammered.
    Basically, I just want to learn how to take the fluctuating, ripply, dirty output from a DC wall-wart, and turn it into a nice, steady, smooth, precise supply, regardless of what is to be run off it. The LED array is already built and works fine off a battery. I just want the option of replacing the battery with a mains supply, and would like to know a bit more about turning fizzy, wobbly, crunchy power into smooth and creamy power, rather than just buy a supply that's already regulated.
     
  4. BobK

    BobK

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    Jan 5, 2010
    You would use a voltage regulator. A very common one is the 78xx series. A 7806 will regulate to 6V at up to 1A. However, your wall wart will need to be at least 8V to get 6V out.

    Bob
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Beware that your power supply may have a lower impedance than your batteries and if you have ignored advice on how to correctly drive LEDs you may be in for a nasty surprise when you connect it.

    I'm not saying you have ignored advice, this is just a general warning which may just be here for the benefit of others who may want to replicate your idea (and clearly mains power is more attractive than running down batteries all the time).
     
  6. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    Another option would be to buy a modern wall wart that uses a regulated switching supply circuit. These are relatively cheap, fairly accurate, and light and compact.
     
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