I changed all my GU10 halogen bulbs for led lamps , and they all work fine except on one of the units where are the lamps are still slightly on even when the lights are switched off. So i think there may be a low voltage going to that set of lights all the time ,Any idea where to start looking
LED lights not switching off completly
Mar 26, 2011
9 Replies
Switched neutral instead of live? Also causes CFLs to occasionally flash after switch off until they have cooled down. Or maybe simple induction from adjacent wiring or live in the same cable.
Modern LEDs need sod all current to glow dimly. I bought an external HD case that had a blue LED on it that was terribly bright. Thought I'd just insert a series resistor to reduce the brightness. After trying 10k and it still being to bright I started to investigate the current it was taking, during that excercise I fould it would glow with just the leakage through me with dry fingers lightly ouching the wires. Eventually fitted a resistor that limted the current to 50uA (micro amps) and it's still on the bright side...
Stick a bit of tape over it? :-) Don
My feeling is that the coupling is more likely to be capacitive than inductive. Same principle as the voltage tester screwdrivers with the LED in the handle.
I did a bit of investigation and switched neutral is not the issue does the same either way round. However I found the following
If the wires to the switch are connected to the lamp, even if the switch is disconnected and the wires are not touching the leds are on slightly. I thought something may have pierced the wire, but when i tested the wire to the switch, even with the switch connected and off there is no link between wires, not even at a very high resistance, my meter shows OL (i/e no connection). So i am putting this down to current induced by magnetism in the wires
Any thoughts
unfunny... I did just that on my computer case (insulating tape) then poked a tiny hole with a pin so that I can see the light. Well, this is a diy group. :)
Exactly.
Yes, for there to magnetic induction there needs to be a reasonable current flowing. Capacitive coupling will allow the tiny amount of current required to make the LEDs glow to flow.
Stange that it's only happening with one bulb. Has the bulb been swapped with one of the others to see if the glow moves or not? If it does it's something odd with that bulb if not it's the wiring being different.
That's a neon isn't it, not an LED?
Indeed. Sorry.
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