LED lights see voltage

Old 10-17-17, 07:25 AM
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LED lights see voltage

This might be more of an electronics question but I'll start here. I have an LED worklight that glows slightly even when switched off. When unplugged from the receptacle the led's go completely off. Even more curious is that only part of the led's glow when switched off as can be seen in the photo. The fixture has a ground provision as does the led "bulb" wiring. Anyone venture a guess as to how this occurs? Is it somehow picking up voltage from the neutral which is not switched?
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Old 10-17-17, 07:57 AM
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Since it's plugged into a receptacle, I'm assuming that it has it's own switch in the unit? Or is the receptacle controlled by a wall switch?

I don't know how much this will help you, but this is common on our trucks with LED lighting when road salt causes corrosion build up in plugs. This corrosion has a high resistance and can put a little voltage to lights making them glow.

What I would do is unplug it and ohm out the switch (if the unit comes apart to get to it). See if there is dirt or something that is not letting the switch turn completely off. I had a similar situation with a table saw once. It had a faint hum when plugged in, but worked fine otherwise. The problem was the switch.
Old 10-17-17, 07:58 AM
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I'd say it's a poor quality light and power is leaking through to the emitters even when off. I would unplug it when you are not using it. If it has a flaw like that who knows what else is wrong with it and I'd hate for it to start a fire when nobody's around.

I have gotten LEDs to do what yours is doing by varying the voltage fed to them. Not all LEDs illuminate at the same exact voltage. There is always some variation. There is a slight amount of current leaking through to your LEDs. It's not enough to light them all but just enough to get some to glow. If you were able to turn up the power slightly more you'd see more LEDs light and the ones that are lit would get brighter.
Old 10-17-17, 10:24 AM
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LED's require very little current to glow. Is the on/off switch illumintated? That can cause this phenomena.
Another fix is to put a small load across the lamp, like a 5W bulb or maybe even a cell phone charger, etc.
Old 10-17-17, 10:33 AM
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There is a ground wire provided in the cord but you may find it's not connected inside the light.

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