LED snubber

[Andy Burns]

A friend has been changing ceiling lamps for LED models and in one room (with a long run of the switch drop cable likely bundled with other cables) has an issue of the LEDs having a low background glow.

Tried fitting a "random" X2 cap across the switched live and neutral within the lamp, but no better, he swapped the fitting for a different type which he though had cured it, but it turns out only made the glow less noticeable, how likely would an FLA01 be to fully fix the problem?

Someone else seems to have suggested a ZBZVM, but I can't find much info on it, but seems more like a surge suppressor

[tabbypurr]

It's not a problem & doesn't need solving. If you must stop it, you need a larger cap with series resistor.

NT

[Andy Burns]

My friend says otherwise

Suggested values anyone?

[tabbypurr]

experiment. I'd start with 0.1 & go up from there.

NT

[Andy Burns]

The one tried was 0.15uF, how much difference would a 100ohm series resistor make, given the capacitor has a reactance of 21kohm at mains frequency?

[ARW]

A big difference.

I would put money on the FLA01 working. I forget what was inside but it was only a cap and resistor.

[tabbypurr]

it's a pretty good way to keep the cap from killing the switch.

NT

[Johnny B Good]

Or even vice versa. :-)

[Brian Gaff]

I find this interesting as I remember the same issue on some old fachioned neon bulbs in equipment merely glowing cos the leads were close to higher voltage AC ones in the equipment.

I'd have thought considering that the led lamps have some kind of psu in them that this should not happen. Maybe its down to the type of bulb, ie lots of leds in series or something making it not need a sophisticated power supply.

Brian

[Andy Burns]

I think it applies to the type of lamps that just have a capacitive dropper plus rectifier feeding the LEDs, rather than a switching PSU.

[Andy Burns]

Apparently it was better at reducing the glow, but didn't stop it.