LED lighting question.

Discussion in 'General Electronics Chat' started by IByte, Jul 24, 2014.

  1. IByte

    Thread Starter New Member

    Jul 18, 2014
    3
    0
    I have this LED clip on lamp that I got at Lowe's. I had one already that put out a nice white light so I have it clipped above my headboard for reading. Even though the first has 3 bulbs out I figured I'd buy another one to clip to the edge of my work table for additional lighting. Same packaging but purchased about 6 months apart. Only this one has 2 distinct issues 1) it has different color light...it's more of the yellowish color. Pulled both apart and they seemed to be manufactured identically. Guess the bulb batch was different? Not that major of an issue, but 2) is major! After about 1-2 min of warm up time it begins to shut off for about a second then comes back on. It does this pretty much nonstop and in no discernible pattern. The power supply says it's 10.5v but when I meter it where the power supply wires are crimped to the PCB wiring I get about 9.9v. Get ~2.85v across each of the LED's. Unfortunately the switch is snapped together and disassembling it may destroy it. Same with the power supply. Sound like a heat or a voltage issue? So here's a thought I have...the supply does say 10.5v @ .xA (can't rem what the current was right now & I'm at work). My bench power supply is currently an old 200w ATX PC power supply but I can't rem the amperage on the 12v rail off the top of my head. If it's near the lamp's power supply amperage can I hook the lamp directly to it? :confused: Maybe I should just take it back, swap it for a different one and hope for the best?

    Guess I'm just curious about LED function and what I can do with it. Might as well take this opportunity to learn something! Any info/advice from you would be much appreciated.

    Oh, one other issue that comes to mind after reading a few of the lower reviews at the Lowe's site; flicker! My eyes are fairly sensitive to 60hz flicker. Old school CRT's nearly kill me! I noticed this with the first lamp but it's only an issue if I am looking at it. It's not noticeable when reading under it. Just another issue with it that I wonder about fixing or if I'm stuck with the seizure inducing flicker? :rolleyes:
     
  2. BobTPH

    Active Member

    Jun 5, 2013
    782
    114
    I would return the second one for a replacement, it surely is not supposed to cut off after a few seconds. I would say it is faulty.

    Bob
     
  3. IByte

    Thread Starter New Member

    Jul 18, 2014
    3
    0
    Thanks for the reply! Think I'll take the second one back and hope the replacement works. If not, I'll go all McGyver on it to see what happens.
     
  4. to3metalcan

    Member

    Jul 20, 2014
    228
    23
    I don't know about big power LED's, but in the small 2V variety, if they aren't lighting the right color, that can be a sign they're dying, usually due to over-current (which would also explain the voltage sag.)
     
  5. tom_s

    Member

    Jun 27, 2014
    285
    333
    could also be a different batch of LED's with an alternate k rating.
    3000k ~ yellow
    4-5000k ~ white
    6000k+ ~ blue

    comparison - most CFC's nowadays give you the K rating (warm white / daylight / etc)
     
  6. IByte

    Thread Starter New Member

    Jul 18, 2014
    3
    0
    Thanks for the replies. I did exchange it for a different one. The newest unit seems fine and the bulbs are closer to the white of my original lamp. Not quite there but certainly closer than the bad unit. And it's not switching itself on & off. So it looks like i won't be electrocuting myself and/or blowing breakers with this one. But have no fear, I'm sure a fun project will find its way to me shortly!
     
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