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LED lighting without power source

Discussion in 'LEDs and Optoelectronics' started by ADRT, Nov 25, 2014.

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  1. ADRT

    ADRT

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    Nov 25, 2014
    Has anyone ever seen an LED light up without a connected power source? I have a large amount of LED Christmas lights on my porch and every so often one will be faintly light or will blink on and off without the cored even being plugged in. Seems to happen more often when it is warm and humid/rainy out. Very random in that it's not always the same LED every time.
     
  2. Fish4Fun

    Fish4Fun So long, and Thanks for all the Fish!

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    I would not say that is "normal" behavior....could be several things causing it....but they are all something of a stretch...if they happen to be in close proximity to a an AC mains line carrying high current I suppose it is possible you might get a "transformer" reaction into the led wiring that might induce enough localized voltage to occasionally light an LED.....if you hadn't said it was more prevalent in the rain, I might have thought there were some type of static charge building up....but that is highly improbably in humid rainy weather....perhaps if the air were highly ionized from a "pre-lightening" event...but that again seems improbable....while it is a real stretch, you might have some grounding issues in your Mains supply that the humidity somehow allows to enter through the plug or perhaps an exposed wire somewhere in the strand....But in general LEDs don't just "light on their own"....they require some type of power input....

    Fish
     
  3. hevans1944

    hevans1944 Hop - AC8NS

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    I have never seen what you describe, but it is possible that all that exposed wire could act as an antenna. And if there were a nearby source of radio frequency radiation perhaps it could be rectified and used to illuminate an LED. This is just a guess. Alternative (non-electronic, off-topic) guess: poltergeist?
     
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  4. ADRT

    ADRT

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    That's what I thought as well. My mains come in just around the corner from the string of lights. I highly doubt that my residential 220vac service is putting out enough EMF to induce voltage. Again this is with the entire light display unplugged. No possible connection to any live source of energy even from a short. The only thing that I could think was some kind of faraday cage reaction with static/ EMF? Makes no sense to me, and it,s only one LED on the string at a time. Never more then one or the LED right next to it. Always just one LED and never the same one on any given event. For example this has been going on all night sense I noticed around 4:30 pm. It is now 9:12 an the same LED is still faintly lit even with the corde unplugged and no other possible power source.
     
  5. ADRT

    ADRT

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    Lol. My wife said the same thing about the poltergeist. There is a large transfer station down the road from my house about maybe 100 yards away. Also high voltage lines running close to my front porch. Probably 4160vac at least. They are about 30-40 ft in the air and 20 ft to the pole from my porch.
     
  6. ADRT

    ADRT

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    Ok so I went and looked again and there are several other LEDs faintly on or flickering. This has got to be some kind of EMF. image.jpg image.jpg
     
  7. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    If there are no outside lights, perhaps the next time it's foggy, you could wait till the middle of the night and put a camera outside with sensitive film and leave its shutter open for a few minutes. Maybe you know someone who's into photography who would do it. You might get a pretty cool picture. Include the LEDs, and the power lines if you can. If you do it, please post the pic(s) here!
     
  8. BobK

    BobK

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    I think you have answered your question. Is there a reason you did not include this info in your first post?

    Bob
     
  9. ADRT

    ADRT

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    Not really. Only that I wouldn't expect it to put off that much EMF to induce enough voltage to light the LEDs. Especially from that distance. Now that I think of it though it's the only plossable answer.
     
  10. BobK

    BobK

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    I would be careful around coils of wire at you house!

    Bob
     
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  11. Gryd3

    Gryd3

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    Free Energy ?
     
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  12. ADRT

    ADRT

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    Still makes no sense to me. Tonight is colder then last night with the temperature dropping and no lights. Last night they where lighting up all over the string. Like I said seems to happen when it is warmer. Not sure how this would affect the EMF from the power lines. Wouldn't it be there even in colder temps? I'm an industrial electrician and instrumentation tech. And I have my masters electrician listener so I'm certainly not a nooby when it comes to electricity or electronics. Just seems like a very odd phenomenon to me. Wish I had an EMF meter. Going to try and get a voltage reading with my multimeter tomorrow night.
     
  13. Gryd3

    Gryd3

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    It could also be related to the current electrical demand for the line near your porch.
    Considering what you are trying to read though, it could be a large host of factors... and if it's only 1 or two LEDs that are only momentary it may be hard to actually measure.
     
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  14. ADRT

    ADRT

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    Some of them actually stay on. The one in the picture from earlier post was on all night last night. I would expect to see at least millivolts. My good fluke process meter is at work so I can't try tonight anyway, but with no lights turning on I don't think I would see anything anyway.
     
  15. Bluejets

    Bluejets

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    We use volt sticks or non-contact voltage detector in our work for quick reference.
    We left one sitting on the dash of the work truck noticed how the buzzer and the led would activate when we would go under the HV on the highway.
    Probably from at least 50 metres either side.
    Now this is 66KV or more but the principle is the same.
    Also, I would like 2 bob for every call I had from "spooks in the verandah fluro", tube would glow without switched on from small rise in neutral voltage, more than likely dry weather when the earth stake area was bone dry.
     
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  16. ADRT

    ADRT

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    Yeah I'm not sure what kv the high voltage lines are outside my house. They fead a decent sized transfer station that supplies electricity for one side of the town. I was thinking 4160 but it could be much more.
     
  17. hevans1944

    hevans1944 Hop - AC8NS

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    Yeah, a sensitive EMF meter is not just for microwave oven leakage tests. It's also a "valuable tool," used along with infrared cameras to detect paranormal activity for television production shows. Maybe you should call a producer of such shows, or at least a local TV news station. Everyone deserves their fifteen minutes of fame!

    The high voltage power distribution lines nearby are the more likely explanation, but don't ignore your wife: it could still be a Holiday Season Poltergeist (HSP). Try setting out a glass of cold milk and a plate of warm cookies on the porch overnight to see if that has any effect.:D
     
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  18. Fish4Fun

    Fish4Fun So long, and Thanks for all the Fish!

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    @ADRT....& High Voltage Near By....That seems the most probable....it is hard to guess exactly HOW it is happening, but it is almost certainly some type of transformer coupling of the twisted wires in the x-mas light string with stray EM waves from the power lines.....to test this theory you might take some aluminum foil and make a "U" that you can place over the "lit LED" as an "EM shield" (I would make it at least 18" long....)....if the LED turns off with the shield over it then you have the answer....WRT to it being more frequent when it is "warmer"....only thing I can think of here is that an LED's Vf drops with an increase in ambient temperature....and any particular LED's temperature increases as current flows through it....so it is **possible** the randomness is a combination of the semi-variable EM field eventually slightly elevating the temperature of a single LED enough so that it's Vf is slightly lower than the surrounding LEDs and then that particular LED becomes the lowest impedance path...AND that below a certain ambient temp the Vf is simply too high....but that is still a WHOLE LOT of assumptions.....If the "shield turns them off" then we can at least close the book on "where the power is coming from"...lol

    Fish
     
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  19. Arouse1973

    Arouse1973 Adam

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    Airs ability to hold moisture changes with temperature so it's resistance will change. It will increase when the temperature is lower, also as mentioned the LEDs forward drop could be a contributing factor but It depend on the change in temperature.

    In your picture I guess your lights run over your head and down the other side also? What are they attached to, is it a metal frame or plastic coated metal?. Does this fixing go through the porch floor and into the ground by any chance.

    Looks like the lights are a joule thief :) It's just working out the most likely cause.

    Adam
     
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  20. ADRT

    ADRT

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    .
    The lights are attached to wood. Not much in the way of metal. The light sets are icicle lights and there are two sets twisted together. A white set and a blue set. They also attach at one end to some lights that go around the railings and some more twisted in garland around the posts. image.jpg The picture of the power lines is taken from my front porch. You can see the pole in the background of the pic of the lights on my porch. image.jpg
     
    Last edited: Nov 27, 2014
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