LED Trouble!! Help me please!

  1. #1
    tk9950's Avatar
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    Dec 2006
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    Keller, TX
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    LED Trouble!! Help me please!

    I hooked up this:

    http://www.radioshack.com/product/in...entPage=search



    To a 9V and used a 270 resister on a switch. I followed the diagram from this:


    http://ledcalc.com/#calc


    But my 9V is becoming extremely hot!! Do I need to upgrade to 4 AA?

    Thanks!

  2. #2
    mrgr8ness's Avatar
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    Re: LED Trouble!! Help me please!

    Hmm...you should only be drawing just over 20mA, a standard 9V shouldn't have a problem with that. I am assuming you have everything wired up in series, like the diagram? Did you try a different battery? If that doesn't help, try upping the resistor size to 330 ohms, and see if that helps.

  3. #3

    Member Since
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    Spain
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    Re: LED Trouble!! Help me please!

    I think that this is its max. not?

    3.2V (typical), 3.8V (maximum) So it should be a 270 resister, but as mrgr8ness has said, use a 330 ohms.

    Maybe I'm wrong, I don't know

  4. #4
    Darth_Nickel's Avatar
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    Re: LED Trouble!! Help me please!

    do you have a switch?

  5. #5
    tk9950's Avatar
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    Re: LED Trouble!! Help me please!

    yeah I have a switch. I just tried 2 9V same problem. Then I tried hooking it up to 4 AA burned the plastic holder. I have it rigged to try 8 AA but I didn't think one LED would take 8 AA to run it. Could I add another resistor on it with the one I have or do I need to completly tak the old resister off and add the new one. Is the switch the problem?


    I have a rocker switch do I even need a resistor?
    Last edited by tk9950; Jul 30, 2008 at 5:33 PM.

  6. #6
    Lucksy31's Avatar
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    Re: LED Trouble!! Help me please!

    Sounds like you might have the + and (-) reversed on the battery input.

  7. #7
    tk9950's Avatar
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    Keller, TX
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    Re: LED Trouble!! Help me please!

    Well I have red to red and black to black and the LED is coming on. Notninja said maybe I am using too much battery. Since it's only 3.5 max volts and I am using a 9V. I am going to try to up the resistor to a 330 and lower the battery to 2 AA or 22 AAA and see if that works. Any other ideas?

  8. #8
    Jango's kid's Avatar
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    SW Minnesota, very small town
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    Re: LED Trouble!! Help me please!

    I've never had any luck using a 9v with leds. either the bat gets hot or burns them. I usually use watch batteries with leds.
    D

  9. #9
    gbeef's Avatar
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    Re: LED Trouble!! Help me please!

    just get a 2XAA battery holder then you'll be fine forget the 9V..

  10. #10
    Darth_Nickel's Avatar
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    Ohio
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    Re: LED Trouble!! Help me please!

    I use 9v for my leds all the time.

    It sounds like to have a short. I made a similar mistake the first time I wired mine.

    Make sure you have both reds (one from Led and one from Battery) on the 2 switch posts (doesn‘t matter which one goes to which red). The black from the battery goes directly to the black on the led to complete the circuit.

    Does that make sense?



    BTW… the batteries that got hot or probably now shot (once you fix the short). Get some new ones once you finish the circuit.

  11. #11
    Darth_Nickel's Avatar
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    Ohio
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    Re: LED Trouble!! Help me please!

    I think I did this right. Sorry for the bad drawing...

    Don't let the + - confuse you on the switch. I should have just put post 1 vs post 2... sorry.


  12. #12
    tk9950's Avatar
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    Re: LED Trouble!! Help me please!

    Well that explains it!!! I thought on the posts on the switch one was for + and the other was for -. So I guess the switch just needs to break the circuit on the positive side. Ok thank you everybody! Thanks Darth Nickel you think it was a bad diagram but it was perfect! Sometimes I need crayons and paper to get it.
    Last edited by tk9950; Jul 31, 2008 at 6:06 AM. Reason: uh...grammer

  13. #13
    Darth_Nickel's Avatar
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    Ohio
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    Re: LED Trouble!! Help me please!

    You are very welcome. I did the same thing when I wired my first LED. After I figured out the problem, I then got a little afraid the battery could have exploded

    BTW.. other lesson I learned. No matter HOW bad you want to see a LED color DON'T "test" it without a resistor... LEDs don't like too much juice. No light, just electronic fry smell and a little burn on the finger if you catch my drift.

  14. #14
    mrgr8ness's Avatar
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    Central Upstate NY
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    Re: LED Trouble!! Help me please!

    Oh, so you had the switch across the battery? Yeah that would explain it, you were shorting the battery out. When the switch was open, your LED probably worked.

  15. #15
    tk9950's Avatar
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    Dec 2006
    From
    Keller, TX
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    Re: LED Trouble!! Help me please!

    Well I had to replace the switch and re-wire everything but it works!!!! Thank you everyone! And yes DN I toasted about 4 LEDS before the resistor.

  16. #16
    tk9950's Avatar
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    Dec 2006
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    Keller, TX
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    Re: LED Trouble!! Help me please!

    Well here are the pics of the finished version. Yes...I like blue.....





  17. #17

    Member Since
    Sep 2006
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    12

    Re: LED Trouble!! Help me please!

    Hey TK9950 - I've been burning stuff up so I'm thankful for finding this thread. Do you remember what kind of switch you got from radio shack for this setup?? gracias

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