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Connecting 200 LEDs to AC (120V)?

Discussion in 'Electronic Basics' started by Homer, Sep 13, 2006.

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  1. Homer

    Homer Guest

    Hi All,

    I am planning to remove the light fixture from one of our rooms and put
    200 LEDs instead. LEDs are going to be:

    Reverse Voltage:5.0 V
    DC Forward Voltage: Typical: 3.4 V Max: 3.8V
    DC Forward Current:20mA

    How can I connect them all to a AC outlet (110V or 120V? in Canada).

    I believe I need to put a "bridge rectifier" to prevent blinking and
    they should be mixture of parallel and series.

    Thanks if advance,

  2. Why?
  3. Homer

    Homer Guest

    The same reason that people put Halogen instead of old bulbs.
    it's cool and looks better (in my point of view)
  4. Guest

    Don't top-post. Just buy LED bulbs. Don't build your own. Did you ask
    how to connect tungsten wire by yourself to 120V instead of buying
    incandescent bulbs?
  5. Joel Kolstad

    Joel Kolstad Guest

    That's not really a fair comparison. A fair comparison would be someone
    asking to build their own (120V) Chrismahanukwansika lights by stringing
    together a bunch of low voltage (e.g., 6V) bulbs...
  6. Well, no, you wouldn't, because you can't buy vacuum in small
    quantities. (;-)
  7. LED's aren't rated to go open circuit on 110 VAC. I'd use a transformer.
    Yes, you'll need a bridge rectifier unless you wire them back to back which
    means twice as many.
  8. Four strings of 25 LEDs in series each with a 1k2/1W series resistor. These
    strings in parallel and connected to the rectifier.

    petrus bitbyter
  9. Bob Myers

    Bob Myers Guest

    You USED to be able to, though...I remember the local
    drugstore had small glass vials of vacuum available for sale,
    right next to some electronic thingy that was supposed to be
    able to test them and (I guess) tell you if the vacuum inside
    them was still good....

    Ah, those were the days...

    Bob M.
  10. Genome

    Genome Guest

    I do not believe that you would be able to connect 10 Leds together and make
    them look good, let alone 200 of them.

    So, before I am interested, I would like to see some aesthetic proof of

  11. colin

    colin Guest

    Well at the risk of telling you how to do something that might get you
    electricuted if you dont know what your doing ...

    You could try and string 25 leds in series, this gives 90v fwd, youl have 8
    of these strings
    conect them in parallel pairs, then conect two of those pairs in anti
    add a series resistor wich I estimate about 250 ohms, but might be best to
    start with say 1k

    repeat for the other 4 strings.

    conect to safety isolated 115 supply, stand well back, push switch with a
    long broom,
    .... fetch fire extinguisher, wish youd got some1 watching at a safe distance
    to ring for ambulance ...

    Colin =^.^=
  12. Genome

    Genome Guest

    Exactly, but that is just your own perception of things. I also have a large
    volume of empty head and would have problems with selling it due to the

    However, I am sure that you might be able to create the experience.

    NOM - No Offence Meant

    Yes, I know about the Governers attempted homosexual adventures with what
    turned out to be a woman. Is it relevant to your 10% or your new request for
    15%?. Is it relevant that your wife makes a really poor man?

    I can get this built next door. Ugly Bitch.

    This e-mail in no way represents the opinions of any people who might be
    made to look bad if they were associated with it unless you were the person
    who was meant to receive it in the first place which is OK because we have
    more dirt on you than you would care to imagine and we'll make some more up
    and it will stick.

    If you have received this e-mail in error then please delete it immediately.
    Do not even consider the possibilities. The consequences are something you
    do not need to deal with.

    Thank You
  13. BobG

    BobG Guest

    120 x 1.414 gives 170V peak after the rectifier. So I'd try 4 strings
    of 50.

  14. Buy? What, are you crazy? When I was a kid we had to make our own
    vacuum with homemade hand cranked vacuum pumps! Of course, the jerry
    rigged diffusion pumps were a lot harder to crank, to finish off our
    home brew CRTs!

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  15. You had hand-cranked vacuum pumps? We had to get six kids into line to
    suck simultaneously.
  16. Simon Dice

    Simon Dice Guest

    colin ha escrito:

    I have conected 5 strings of 34 white LEDs (5mm) to a rectifier bridge
    with a current regulator (LM317HV)(for each string) and it works fine...
  17. Oops. 200 LEDs require 8 strings of 25.

    petrus bitbyter
  18. nospam

    nospam Guest

    Transformers are not rated to go open circuit on 110 VAC either.


  19. Only six? That must have really sucked!

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  20. John Fields

    John Fields Guest

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