L.E.D Lamps Staying on

[gary174]

Hi Everyone,
Wondered if anyone can help. I am a domestic installer and have recently changed some GU10 50watt lamps for some GU10 3.6watt L.E.D lamps. They seem to work perfectly except for the fact that they seem to continue glowing, very slightly once the power has been switched off. They have been fitted all day and are still on, i do realise that some L.E.D's can stay on for a little while after the switch has been turned off but these are staying on continually.
Can anyone spread some light on this for me.

Many thanks

Gary

 

[Inteificio]

This must almost be the most asked question of all!

Could be a few things.

First of all you have to understand that unlike resistive lighting LEDs get more efficienct the less current is going through them. Even 1 electron trickling past with pump out a photon.

magnetic induction from nearby circuits can cause a minute current to flow in the wires, this can slowly charge up a cap in the circuit until enough energy builds up for it to trigger for a fraction of a second.

if they are staying on for a long time after switch off, my money is on a slowly discharging smoothing cap.

Basically the electricity was always in the wires, but only the LEDs are efficient enough for you to see it!

To get rid of it, just stick a high value resistor across the terminals, this will stop to the electricity building up and allow the cap to discharge.

As I was first response, does this mean I get a thanks ;-)

 

[JD6400]

Oh , go on then !

 

[Engineer54]

This must almost be the most asked question of all!

Could be a few things.

First of all you have to understand that unlike resistive lighting LEDs get more efficienct the less current is going through them. Even 1 electron trickling past with pump out a photon.

magnetic induction from nearby circuits can cause a minute current to flow in the wires, this can slowly charge up a cap in the circuit until enough energy builds up for it to trigger for a fraction of a second.

if they are staying on for a long time after switch off, my money is on a slowly discharging smoothing cap.

Basically the electricity was always in the wires, but only the LEDs are efficient enough for you to see it!

To get rid of it, just stick a high value resistor across the terminals, this will stop to the electricity building up and allow the cap to discharge.

As I was first response, does this mean I get a thanks ;-)

There you go.... you got two out of it!! lol!!

 

[DaveyD]

Ok then ... if the cap fits

 

[Rauer]

Here's another query I have on l.e.d lamps , hopefully I won't have to start another thread on it, I have fitted some collingwood led lights in my plinths at home my other half says she sometimes sees them flash, I am yet to see it!! She is asking me why they do it , they are installed on the ring and I only have 1 ring in my house I am yet to start rewireing, any ideas

 

[Specialist]

Hi mate: probably as said above, due to induced AC in the wiring.

 

[Rauer]

That was my thought but with their being a driver thrown in there I was unsure if there was something in that to stop it , and she was seeing things!!

 

[ringer]

I am far from being an expert , but are there not two types of LED lights, being constant current (240V supply) and constant voltage (12V supply)? The additional resistor across the terminals would only work for one type and not the other. I stand to be corrected if misunderstanding.

 

[Rauer]

U can put it across the 240v end tho I.e before the driverThe 240v ones usually have a built in driver

 

[Silly Sausage]

I am far from being an expert , but are there not two types of LED lights, being constant current (240V supply) and constant voltage (12V supply)? The additional resistor across the terminals would only work for one type and not the other. I stand to be corrected if misunderstanding.

Probably clearer to say, put high value across the switched live and neutral, to discharge the circuit.
It's in parallel with the lamps so has no effect on them.

 

[Specialist]

That was my thought but with their being a driver thrown in there I was unsure if there was something in that to stop it , and she was seeing things!!

Do you really want to tell your missus she's seeing things ?:lol:

 

[Rauer]

She always seems to measure things on the small side !hahaha

 

[wildgoose]

Looking for a simple solution:-
If both the live and the neutral to these LED lamps is isolated at switchoff using a double pole switch, then I would be very surprised if they still glow!! If they still do, then they are probably living off capacitance from inside their own power packs but this should only be for a short period.

Double pole grid switches are great and they look like the normal single pole light switches.

 

[La Poste]

That's an interesting solution, double pole switches.