Electronically controlled LED lamps glowing when off.
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- เผยแพร่เมื่อ 5 ก.พ. 2025
- LED lamps (and some fluorescent ones) may glow or flash when they're supposed to be off when used with electronic switching devices like solid state relays and dimmers. Here's why.
The main reason is usually the snubber network across a triac. This is usually a resistor and capacitor connected in series and appllied across the main terminals of the triac to attenuate sudden high speed glitches and transients that could result in the triac turning on when it wasn't supposed to. Triacs have a characteristic called DV/DT Where the D stands for delta, meaning "change in" so the characteristic relates to change in voltage / change in time. This relates to the triacs ability to turn off or remain off when a rapidly rising waveform is applied across it, like a pulse or transient. Typical values for a snubber network are 100 ohms and 100nF. Normally with a heavy load the capacitive coupling through the snubber network is not an issue as it gets shunted by the load. But with very low loads like LED lamps or small motors it may cause a situation where a lamp keeps glowing dimly or a small effects motor keeps running or shuddering slightly.
In some cases you can solve the problem by using another snubber network across the load as it then forms a divider with the one across the triac, and that can lower the leakage voltage to a level that the affected loads will not light or move.
A common approach to solving this issue in the theatre industry is to use a ghost load where a traditional lamp is used to load down a dimmer circuit controlling a small effect, and also help ensure the channel turns on properly, as triacs need a minimum holding current to remain latched.
If you enjoy this channel you can help support it with a dollar for coffee, cookies and random technical stuff at / bigclive
I don't understand electronics at all, but i find myself coming back to watch more. Maybe it's the soothing voice and gentle accent, but i've spent hours watching these videos
+Plum Bit Your comment is tripping me out. I was honestly about to write the exact same thing in the comments.
Snootches Bootches Maybe we find it therapeutic ha
+Plum Bit I believe so. Ill probably come out of this with some knowledge of the organs of electronics as well , which is great.
+Plum Bit I know nothing about electronics and next-to-nothing about electrical engineering. However, after having seen several of Clive's videos, I've started to become less and less confused when he traces circuit diagrams. I've started to learn to expect where _bridge rectifiers_ or _smoothing capacitors_ are going to show up. Microcontrollers still throw me, though. To say nothing of TRIACs.
Yes he has a smoothing voice and he does not cut a lot out of his videos, this I do like, I hate it when there is so much cut out you have to try to put together what they have done. Clive has a way of getting it over what he is talking about and the schematics with explanation is very good way of doing it.
If you watch enough of his videos you will start to pick things up, even if you have never worked with electronics. I like it when he moves on to do simple circuits other than lamps. Maybe he will explain what a Diode, Resistor, capacitor, Electrolytic capacitor does, though I think he did this in an earlier video
7:40
>capacitor (draws resistor) and resistor (draws capacitor)
Well played sir.
Juan Herrero lol
oh well, at least it is a linear system :)
I've got to thank you Clive, I put in a ceiling fan recently and the LED bulb would always stay on at a low level after switching it off and I thought it was a fault with the fan. I swapped the bulb for a halogen one (seems they don't sell incandescent bulbs anymore) and it works perfectly. This video saved me the effort of taking the whole thing out and replacing it for no reason so thank you!
One of those quack power saving devices (PFC capacitor) connected in parallel with the lamp would probably stop the flickering/glowing, without taking much power. Hey, they may actually be useful!
Can I suggest a video where you experiment with a couple of solutions to this problem? I know you suggested some things to try but it would be neat to see them in action and I think it would get a bunch of views.
WOW, Thanks ! I just spent 2 hours trying to figure out why my SSR was showing "almost" full voltage across the Output side, when NO input was present.....
I thought I wired it wrong...and you showed me what I had an assumption about - SSR are NOT "Old Fashioned" coil relays that make a NICE noise when opening and closing!
I have that glow problem with my X10 controlled wall switch controlling 5 kitchen spots. Initially I installed fluorescent and now Led bulbs. Intuitively I installed one incandescent with the fluorescents and continued when I swapped them for the LEDs. Both types needed the incandescent. Now I know why the problem occurred. Thanks for the enlightenment.
I'm so glad you put this up. It explains why some of the LED lights I put into my truck interior lights never completely go off.. couldn't use them. Can't figure a way to fix it even with your helpful suggestion.. Take Care
I had a CFL in my bedroom, standard UK house wiring, no relay, no dimmer, and it would flash about once every 5 minutes when switched off. Thanks for explaining why it was happening! 👍
Clive it would be really great if you could do a follow up where you test potential methods of fixing the issue, since it is so common now with household dimmers and LED lamps. Would be interested to see for each potential fix -- snubber network, just a high value resistor, etc. -- the current draw when "off", the waste heat generated, etc. Thank you!
Thanks for the warning about SS relays leaking enough juice to bite.
Thanks for your experience and clarification, most low cost SSR and dimmers will display same quirks. I wanted to energize a PWM fan array using the USB voltage to activate the solid state relay. Big failure, fans would just keep running at fractional speed with the relay control voltage removed. Two solutions found: Livolo active phantom load, or a PTC implementation.
you answered a long time question! I have and have used for years x10 dimmer modules for remote control and computer timers. now with regular light bulbs nothing but with CFL or led they all flicker. now it scared the £@#$ out of me at 3 am. but I am so used to it now I have a night light! thanks.
Thank you Clive, this has been very very helpful. I have three DMX controlled power junction boxes. Each box has four three-pin-plugs. The boxes, and each plug therein is controlled by a separate DMX controller, which consists of twelve on/off buttons, (so I can run a maximum four boxes of four plugs each.). I've been using them to run a number of LED lights such as Chauvet Swarms, Mini Kinta, Mushroom, spots, and a number of others, for dances and parties. I have never been able to figure out why many of them keep flashing when they were meant to be off, yet work fine when turned on. I had to revert to using normal electric multi plug junction boxes and switching them on manually. I just tried experimenting with a double adaptor, with one outlet going to an LED light and the other to a standard 60W lamp. There was no flashing with both plugged in, but when I unplugged the lamp, the LED started to flash. Once again, thank you. Now I've got to figure out a way of putting a load on to each plug that's the equivalent of a 40~60 watt bulb.
I think the last solution was probably the best. include a higher power rated bulb or device in the sequence with a higher power requirement to shunt the leakage to a device that acts as a threshold to the system. Good video.
I come here for electronics, not art class. You can draw shitty schematics all day, as long as you explain what they do :)
:)
+bami2 Lurid...love that.
I laughed out loud when he talked about the drawing being let's say off standard.
Possible solution: Put an X2 capacitator in parallel with the lamp as a bypass for the leaking current.
NOT for dimmed lamps! Phase cutting produces harmonics. These higher frequencies will lead to dangerously high currents throug the capacitator when the lamp ist powered on.
If a dimmed LED lamp glows or flickers when turned off, use a "Kompensator 6596" from Busch-Jaeger. This is just a PTC in a casing. Bypassing leaking current to neutral, it will get hot an highliy resistive when the lamp is switched on.
My patio has a pair of remote control track light fixtures, each with 3 lamps. I replaced all with cheap LED bulbs, and they'd come on okay, but when off would strobe weakly. I replaced them with even cheaper but dimmable LED bulbs, and they work perfectly.
Adding a plug-in transformer in parallel to the lamp (via a 1 to 3 outlet tap) seems to fix the issue without hooking anything up to the transformer output. A common old+heavy 5-12v DC "wallwort" is best; experiment to find the least vampiric one for your setup. They fix LED bulb issues with SSRs, dusk-to-dawn sensors, motion detectors, lit switches, etc.
There is always a leakage voltage on an SSR .It will allow low voltage low current devices to to stay illuminated .We will switch heater elements through and use a manual motor starter or contractor to disconnect the output going to heaters .Especially at 600V 3 phase heater banks used in commercial ovens .Croydom, Opto,or Carlo Gavazzi they all have the same issues
Found this out recently when I was using a solid state relay to control a neon transformer. Even when it was supposedly off, there was enough current going through the transformer to produce very tiny sparks when the output wires were a fraction of a millimetre apart. Luckily it didn't catch me by surprise, because I was also using the Cliff QuickTest and its neon indicator was also well lit even when the SSR was supposedly off!
If that's a knock-off of a Fotek, would that make it a Fauxtek?
i realize I'm quite randomly asking but does anyone know of a good place to stream newly released tv shows online?
Cool, a channel worth watching!, thanks man!
Loving those dulcet Scottish tones and the information and ideas you provide in your vids, keep it up, you got me interested in electronics again!
Regards and greetings from south east UK! :)
If your going for the one tungsten lamp as shunt for LED circuit concept, you can actually buy decorative large filament lamps. While technically these are much less efficient, they are not designed to light a room, so total current draw is often less, and they have a basically unlimited service life, which is cool given if it does fail, all your LED's will go back to either flashing randomly or glowing when ever the lights are turned off.
Home made SS relays with quadracs ("snubberless triacs") for the win! Relay or dimmer applications won't ever notice the missing quadrant, and the leakage is essentially zero.
Got a link to a schematic for that?
@@tcurdt Yeah I drew one. It is a very basic but functional SSR, not a dimmer. Lets see if TH-cam lets me post the link:
eeberfest.net/etc/SSR.jpg
eeberfest.net/etc/SSR.pdf
Note that the triac MUST be "snubberless"!!
Also if you are using 240VAC you should probably change the 360 ohm resistors to 750 ohm. I've only ever used the circuit (as drawn) on 120V.
@@tcurdt Additional thought for you: if you wanted to fire the SSR using a GPIO pin on a 5V microcontroller (e.g. Arduino UNO) it would be best to substitute a MOC3063 for the MOC3061 shown and use a 470 ohm resistor in the control circuit. Done like this the SSR can be turned on with 5V ~7mA, well within limits of GPIO. As drawn with the MOC3061 and 120 ohm resistor it needs more like 30mA to turn on.
That was interesting, thanks! I think with the continuous spread of LED lamps, we will have to adapt our electronics to them, so change the whole design of dimmers/solid state relays and so on. It's often like that when you change one part without changing the others.
Our old house had a light fitting in our bedroom that had a small leakage current. I remember walking up one night to the CFL bulb in the fitting flashing. It wasn't constant flashing, just a really bright flash every few minutes, then a few quick flashes every so often.
It was a bit freaky until I figured out what was going on. It was a bit like those stupid ghost hunting TV shows :-)
For tungsten lamps it is possible to use two 15W bulbs in series as a resistive load so the power usage is not that high and it takes decades for the bulbs to go eol.
I've been hooked on your videos for the past month now and I don't know why....maybe its your intense knowledge on electronics or maybe it's your interesting accent. either way, i don't plan on stopping watching your videos!!
Clive could you do one of your great videos on building the snubber network to stop the flickering on the LED light and test it. Thanks
had that problem on a CFL, after it was one for a while. every few minutes it flashed very slightly. annoying when youre laying in bed and see this trough your peripheral vision...
I have noticed that glowing effect in a couple of led lights hooked up to a dimmer in my house, and thought it was the lights having the problem. Now I know it's the dimmer's snubber network causing the issue :P
I tried putting a 47K 1/2 Watt resistor across the Live and Neutral wires, going to a 240V led bulb.
After a few minutes the resistor got to around 48 centigrade, and was too hot to touch.
The resistor did not breakdown, even when I extended the on time to 30 minutes.
The resistor stopped the led glowing when the relay was off.
I also tried connecting a wall wart type power supply across the Live and Neutral going to the 240V led bulb. That also took care of the led glow.
So, am I wasting energy, using these SSRS and curing the problem with 'heaters'?
Looks like it is more sensible to use mechanical relays for these problem 240V led applications.
I love these videos, I feel smarter every time I watch them.
Thank you for making me feel smart!
Here in Norway we mostly use 2, or 3-fase 230v, and in certain conditions on single pole lights switches theese LED fixtures will continue to glow dim even when off. Only explanation I could find was capacitive leakage through ground... At night the LED lights are bright enough to navigate in "complete" darkness.
We had this happening with a normal light switch, but it would flash every ~10 minutes. I am guessing it was the ac coupling in the lightswitch and the cabeling (capacitive effects) that caused this. amazing how little power these lamps actually need to give out light!
thanks for giving me info on the! I bought a 100 pack of the clear wago connectors. these look awesome!! thanks guys.
Maybe the pink silicone holder is for hole warmers???
This must be the reason my outdoor halogen light would just flash with a big LED replacement; there must be a triac/snubber in the PIR detector unit. I'll have to get the ladders out and have it all down again!
I have another Problem... I have a LED Strip that just baaaarely glows blue (not even evenly on all LEDs) when it's supposed to be off... Any idea on what could've failed?
It sounds like a very low current leakage that is making it light.
drop a 1K resistor over the terminals and it will eat that leaking current
Good video. Thanks for the detailed explanation. This reminds me of when using a CFL light and with a LED light plugged into to a socket wired to a old use Dimmer replaced wall switch, the CFL and LED lamps would flash even if the dimmer push-to-be-off was engaged. So irritating at night, the dimmer had to be replaced with the normal on/off switch. - I wonder if a pull-down to ground resistor (of some high value to not load down normal operation) between the 'snubber' capacitor and resistor would prevent the cap from charging and discharging in cycles. Yeah, its not worth the bother to modify the Solid State Relay but still in principle, I wonder if that would solve the issue.
I have some CFLs which I fitted in my garden and one of them flashes when off - not always the same one, and not as quickly as the Asda light in the video. But I know why they do this - the outdoor switch that I wired them to has a neon indicator across the switch that comes on when the switch is off, leaking some current to the CFLs. The neon in turn only lights because of the load through the CFLs.
I ran into this problem recently after replacing all light switches in our house with the ones that have the gas-based light indicator(that turns on when you turn off the light). One of the lights in the house is an LED light fixture and when the switch is off, it blinks rather aggressively and frequently(like once every 2 seconds or so). I've been looking up solutions to the problem and I did get four different suggestions:
1. Connect a resistor and a capacitor in series with the light fixture
2. Connect just a resistor in series with the light fixture
3. Connect just a capacitor in series with the light fixture
4. Disconnect the light indicator(duh, but I bought the ones with the indicator on purpose and I'd rather have it work :D )
:D I think I'm going to grab some resistors and some capacitors with different values(suggested resistor values were up to 1 W with resistance between 100k and 1M ohm and for the capacitor either 220nF/400V or 100nF 275VAC) and see if I can resolve the problem.
You could also try a different LED lamp. Only the ones with switching power supplies are prone to the flashing effect. Others will just glow dimly (which can be useful) or not at all.
@@bigclivedotcom true - I'm just being cheap(well and I do want to experiment) xD Other than the flickering it's a perfectly good light - it's not the LED light bulb type, but instead the one that has a bunch of LEDs on a board, so replacing is pretty much getting a whole new fixture, which could have the same issue anyway.
I've temporarily removed the indicator light for now until I can get around to trying one of the other methods.
I'm also curious to know if it's possible to remedy the issue while keeping the indicator light in case we end up getting a fixture with the same problem.
Thank you for the videos by the way! The educational part is well presented and the humour is top notch too!
A quick update on my situation. I've gotten two 100nf capacitors - one at 400V and one at 600V. I haven't gotten around to testing it on the fixture yet, but I did run into an LED bulb that did glow when the switch was off. So naturally I tried one of the capacitors(the 400V one). Lo and behold it did allow the LED bulb to turn off completely when connected in series. Here are two poor quality photos of it working - photos.app.goo.gl/op7HMMT7eDmDthkh7 . You can see the capacitor when the bulb is fully off, and the lack of it when it's glowing.
Side note - adding at least one bulb that doesn't have the problem to a chandelier with multiple bulbs also resolves the issue(I tried it with a different LED bulb that behaved correctly). However the solution with the capacitor can come in handy if you don't want to have mismatching bulbs, OR you can't add/replace things like in an LED fixture that doesn't use bulbs(no idea if that's the correct term :) ).
Not gonna lie - solving this made me squee with joy xD Considering my dad is an electrician and his solution was to just remove the indicator light xD
It's true... Every day is indeed a school day.... For many, many years, I always assumed that the leakage current was coming through the triac / SCR (Delete as applicable). I had no idea that it was actually the snubber network....
Two way switching gives a similar effect here in UK, flickering/dim LED's.
With big dimmer packs it's often not just the snubber network. Most dimmer packs are used for tungsten lamps, and as you most likely know, to prolong the life of the lamps, there's a pre-heat setting on the dimmer packs. This delivers just enough power to the filaments to heat up, but not enough to actually light up. When you use LED based lamps on these lines, they wil light up, because they need so little energy. That's likely what the problem was with the disney dimmer packs :p
Preheat is an option on the theatre packs. It was turned off.
I'm volunteer light tech at a local stage, so that's where I get my info from as far as existing equipment goes ;)
(and electronics engineer... so I do kinda know a bit about the technology... LOVE learning from your videos ;) )
For my elderly mother I wired in a motion sensing switch (built in the wall to replace a normal toggle wall switch, you understand?) and it did this when not triggered on. Let me be clear -- it did this with an incandescent load ...Would this happen for the same reason?
Of course with the Incandescent bulb you did not see a flicker, it just constantly glowed when you wanted to sleep. (it had an adjustable timer for the ON time and a pot for the light and adjusting neither helped.) I thought I was saving money & liked your like playing about with lights & being ahead of the times but in the end it just cost $30 extra to begin with plus loads of my time. Plus I figured it must have leaked like 5-10 watts of power.
It was made by a well known lighting and switch maker, too, I forget the name (its pry in one of my electric tool boxes somewhere in the basement) I really want to buy another but it seems like a waste of money ... next time I will probably just try an automated home hub as I've noticed there are ones that do similar things.
But it was annoying as all get out. Makes me reluctanct to ever buy another one -- if I ever run across the thing I'll try to edit this to add the name because now its bothering me I can't remember that name.
Back in 2008 I fitted the then 1.3w GU10 LED bulbs now here is the puzzle for you. I also was able to see the slight glow on these LED Bulbs the switch was a standard light switch, GU10 has no earth point I never Figured a valid reason of how the LEDs were doing this.
I checked that the switched wire was live the bulb only connected to neutral with old-fashioned 5A wire fuses at the fuse box disconnecting the live wire from the switch - no change standard 1.5mm flat lighting cable white with red and black conductor wires
My only thought was the some kind of eddy current /transformer effect from the steel wall conduit (1950s house that been re-wired using the old conduit that once had the rubber flat cable in)
this answer some of my questions but not all of them. I have a chandelier with a dimmer I recently converted it to LED. I bought a new dimmer I installed it the way the instructions said to install it if you don't have a ground wire I installed dimmable LEDs but now everytime I turn it on it blinks you have to start it out at the dimist level then power it up to full or it just blinks. I'm starting to understand why it blinks but what I need to know is how to stop it.
So i have what may be a doggy question. Is it possible to wire a PTC into the light circuit and have it create a load? I have a friend with a large number of recessed ceiling lights in his house ( 45 ) on 4 different 3 way digital dimmers and he wants to convert to LED but unless he leaves one incandescent in each circuit the whole lot all glow when there off. So my half brain idea was to install a 5 watt 80C 110v PTC heater, one on each circuit mounted to a heat sink inside the cans plugged into the circuit to create a slight dummy load. What do you think.....they generate less heat then the 150w max rating that the metal can it rated for was my thought...
I have this problem with cheap LED's I bought on Ebay, they were $1 each in boxes in 10 a few years ago, they work fine, but glow while off, Name brand LED globes bought locally (phillips etc... 5-6 bucks each) Do not do it, Do they have extra circuitry to avoid the problem? or do they just use enough power (6watts instead of 3 like the ebay globes) that they don't glow from the leakage?
I've had the same pulsing flashes with compact fluorecant bulbs when they have an illuminated switch in the circuit, when the switch is in the off position.
the flashing is actually pretty cool for an outside lamp
incandescent dimmers have the same or similar issue, they usually list their minimum load as 40w or so. Even a 4 fixture with led bulbs wont meet this.
Ive gone back to halogen G9 in my polished chrome ceiling light fittings where Id tried LED bulbs that glow when off. A decent dimmer switch on the wall and they give off a much nicer light anyway. Not a single bulb blown in over 2 years. Im so tired of messing around with expensive LED lighting that just dosen't seem to give off a decent non defused light or as reliable .
bigclivedotcom I've had similar issues with LED bulbs in light fixtures that have "dusk to dawn" sensors in them. I've found that using dimmable LED's have solved the flashing or dimly lit issue. That is to say the dimmable LED's don't seem to have this issue.
Hey Clive, big up from Finland!
iv had two home bargains eco lamps fail very quickly clive, one smells of magic smoke, one was a colour changer, the non color changer has cracked the white coating like fault lines on a volcanic surface and the other seems to have oozed brown from the ir led, thoughts?
Good job. I like your explanation style and follow you.
But I have a suggestion for you. I see all of your videos, you use single side of your note book. Can you use both sides of the paper? If answer is yes then I will be thankful to you. Please don't mind.
I don't because the ink shows through. But each page is shared with tens of thousands of people and then stored.
Couldn't something be added inside the solid state relay so you wouldn't have to mess around with external snubbers and such? I'd think that higher quality solid state relays would have something.
All triacs have a residual current around 7 mA. So if you dont have snubber, you can get the same effect.
In my case, it's not a solid state relay, but a completely physical mechanical switch. Heck, even if I completely disconnect the switching wire to the lamp (and leave the live wire connected) and leave the switch off, I measure anywhere between 25V and 40V on the mains with no lamp inserted. However, when a lamp is inserted, I still measure about 5V on the mains. Switch on, and everything's fine and dandy at 230V. I don't have the guts to measure the current, as I'm not sure if it's ok to short out the wires, as I'm not sure where this power is coming from, and why I'm able to measure anything on a wire that is not even connected to anything...
So, if a dimmer or a solid state relay isn't the problem and the lamp is switch is completely mechanical, why does this problem still happen?
It woudn't be induction, would it? Induction wouldn't cause quite that much voltage, would it?
+thany3 It's a combination of induction and capacitance. The switch seems to have the contacts close to eachother even when switched off, creating a capacitor with a couple of pf. And when the wires to the lamp are beneath wires that currently are transporting high current to another appliance it also could be inductance.
+BloodySword I had a similar issue with 2 light fixtures. For curiosity I put a neon flicker candle bulb in my bathroom. When I pulled the cord to switch it off there was still a very obvious glow at the end of the metal inside the bulb. Turn it on and it was fine. Off had the glow which was weird. The other fitting is in my PC room, It is a 4xGU10 spotlamp bar with 2x5 white LEDs at the edges so you still have light if all the bulbs failed. Well the LEDs failed before any spotlights. I noticed they were wired with a capacitive dropper. I took them out and used 2xBlue LEDs with resistive droppers from a defunct kettle. They work fine for hours at a time. But I noticed the same effect. If I used CFL bulbs with the lights turned off the blue LEDs would still be glowing. If I took the bulb out the LEDs went out, If I used LED bulbs the Blue LEDs stay off until the fixture is powered up... Why ?? Why is this happening? Many thanks :)
***** I *disconnected* the black (switching) wire and left the other one attached. iirc "other one" means the blue (neutral) wire. So it can't be capacitance of the switch, can it? It has to be inductance then?...
Then lemme ask this: why does this not happen for other fixtures around the house? Surely if there's an appliance drawing a huge amount of current (there isn't - the biggest load was probably my fridge drawing
thany3
Mhm. Interesting. :D In Germany, the neutral is shorted to ground, but only in the distribution box of the whole house. From there, neutral and ground are seperated from eachother, meaning, that the neutral wire can collect all sorts of crap being a huge star distributed antenna. Perhaps this is the reason. Don't really know.
*****
I'm not actually sure what happens beyond my distribution board. But I'm pretty sure there's a reason we have a separate earth wire. It sounds like in Germany the neutral acts as an earth wire as well.
It sounds weird to me, because the neutral does go into the electronics bits of your devices... It means a malfunctioning device that puts some sort of current on the neutral might damage other devices around the house. At least more so than when using a separate earth wire.
Anyway, I'm sure it's not like that here, so I shouldn't be able to measure any voltage from the neutral.
Interesting... way back , found there was enough leakage from the wire to wire capacitance in a 2 way stair light circuit to cause atrocious interference from a CFL when switched off - not enough power to light or flicker, but it wiped out AM radio.
I guess you could just put a capacitor between live and nautral to fix this and save 30kW while you're at it.
Ever thought of getting one of those Self-Balancing board/Swegway/Hoverboard thingys and dissect them? Maybe get a cheap broken one on Ebay?
Surprised you didn't try to make the extra shunt to show us how / if it would work.
ghost load? never heard any one say that. Ive heard Phantom load. you learn something new everyday
this problem has annoyed e for ages, tried to create a flotaing ceiling light thing with led strip lights and make it dimmable, but never managed to find a dimmable transformer and a 2 way rf wall switch that work together without the led stirps flashing when the switch was off. :(
I have a weird LED bulb that continues to glow even when unplugged from the socket for hours. It's not always a steady glow, sometimes it will flicker, occasionally glowing bright enough to light up a room for a few moments.
Either there is a really big capacitor in it, or it's picking up electricity from some wireless source, like how a florescent bulb lights up near transmission power lines.
LEDs will glow visibly at just microamps. Some lamps do glow for a long time when disconnected.
@@bigclivedotcom Thanks Clive, I Didn't expect a reply from a 4 year old video.
It is weird to be able to be able to walk around the house with with a disconnected light bulb still flickering in your hands.
@@JamieJamez I think you could play some good tricks with that!
3:55 - Sheesh...I almost choked on the hard candy I had in my mouth when he drew that resistor like some kind of weird fish...LOL Also, when he mentions Disney Paris with the "...clumps of tungsten lamps hanging out of the box...", all I could think was, "I guess Disney doesn't live by the _Jurassic Park_ slogan: 'Spare No Expense." LOL
whats the difference in side an led bulb between a dimable and non dimable lamp
I have a question. Is the bayonet type connectors more dangerous than the screw type?
can you measure the leakage current and/or wattage?
I had a clapper and I guess it put a small current through the plug to check if something was connected because it caused the CFL bulb in my lamp to blink when it was off and caused my DS charger to behave strangely
I could use a PTC resistor to solve the problem?
A ptc does indeed sound like a good solution.
Love the Wago connectors but prefer the 221s, smaller and easier to use.
PS: Thanks for your posted videos.
I have a timer for my outside light. Its one of those pole things with 3 LED lamps in it. It flickers from the leakage through the SSR. Mildly annoying, but I could stop it by screwing in a standard lamp if it bothered me enough.
I use a small 7 watt night light on my flashy blinky led bulbs with the motion detector wall switch. The led dimmers don't seem to have this problem.
Good point: 👏
A. The day night switch has an activation "time delay to eliminate nuisance switching" which effectively isolates the circuit during the light portions of the day. (ie. leakage current used to run a timer)
You may still find that the LED's flicker/glow during the night if the motion sensor is bridged out.
B.1) The leakage current could possibility be used as a backlight and illuminate the wall switch, or
.2) charge a battery.
C. 330nF Cap and 100 Ohm resistor, PTC or gas arrestor combination snubbers (from Line Out to Neutral) only divert the problem & make it seem to go away.
(Inductors in series to the capacitance reduce the overall impedance)
D.1) Double isolation: If regulations allow you could reduce the inherent "capacitance" of the circuit by using conductors WITHOUT earth and keep the lengths as short as possible.
.2) National Regulations forbid the use of 50 Ohm impedance coax cable to reduce transients, due to the insulation material NOT being rated ≥500V/600V AC.
{This is where uTube limits communication because we can't post circuits, photos, graphs & the like} 👎
This reminds me of a flashing joule thief. You add resistance between the battery positive and the coil tap. Add an electrolytic filter capacitor from the resistor/coil tap to ground.
Surprisingly I haven't had this happen yet, but then, I still use mostly CFLs, the only LEDs in this house are the LED filament bulbs and one lone candle-bulb style LED COB down in the living room, kind of sad that they don't put the anti-flicker/glow components in place, but every 0.000000047% of a penny helps I guess... :P
This issue seems to be more common with LED lamps of low wattage such as 2.8 watts. I have found that 2.8 watt LED lamp poses this problem whilst a lamp of 5 watt does not.
Further lamps of same wattage but of different companies behave differently.
Why is it so?
It tends to depend on the fitting of a shunt resistor in the lamp.
I have a coil fluorescent bulb in a fitting controlled with an everyday light switch.
It flickers slightly when off.
I don't think there is a solid state relay involved anywhere in this circuit. Where would be the leakage? could it be the a live wire laying in parallel with the cabling in the roof?
what about having a master off switch before the dimmer to stop all eletrical flow when not wanted.
Good video , I have a tropical fish tank and when I switch OFF the light of the fish tank the light i glows.
I have the same problem with some aliexpress lights, the power supply, when switched off in either live or neutral, can still turn the led slightly on, when the led board has something near, like my hand. I guess it acts like some sort of capacitor, and allows a tiny current to flow, just like thoose screwdrivers that can tell you if the wire has voltage, even without touching it... With thoose ones, i have to use a double switch to cut both live and neutral...
Thank you for the detailed explanation! I was starting to belive that there are ghosts in my computers LEDs 0.o
Even the stray capacitance in the wiring over here makes some LED's with capacitive droppers light up.
Very common, especially on lighting circuits with multi-way switching. I quite like the effect.
Me too,makes nice nightlights and it's very little electricity that would otherwise just go to waste.
I did actually the same with tungsten lamps to a dimmer rack once. But in this case I didnt had enouhg hanging lights so had to find all kind of desktop lights that night. You could guess how funny that must have been looking at a fast switching part.
I had set up a light system onto my car some time ago, and one circuit of it, (being two circuits in the system, controlled by the strobe controller) would sometimes just give a dull glow. Not always, I noticed, but sometimes, it would just barely glow one of the control lights. I'm guessing this is why? It's interesting, to say the least, but I thought something was horribly broken.
great video! but im completely new to this and would like to have a step by step how to install the snubber network? thanks.
So the Impedance for this RC network is ZRC = 26.52601 kΩ. So in a 120 volt circuit @ 60 Hz the current is 4.5 MA.
Wouldn't it be better for your energy bill and the environment to not have any leakage current?
I knew someone that thought they were getting free light, so they connected a few to make it just bright enough to walk about. I just couldn't get it through to him that he was not getting it for free, He was in the countryside so everything was pitch black, so even the small leakage current would light up things just enough to see to get around. It was so funny he thought he was getting very dim light for nothing, about as dim as he was. Strange thing though, give him an engine and he was brilliant. But electric and him did not mix, he even stuck with car electrics. But he could get more out of an engine than anyone else I knew. He even got more out of a motorcycle engine than the manufacturers could. You just have to laugh sometimes!
Hi Clive. I have this problem with a light in our stairwell. It has a dual switch so that it can be switched on or off from either the top or bottom of the stairs. Very annoying and i really want to fix this without wasting power. I have no dimmer and no relay in this circuit. Just a switch at top and bottom of the stairs.
If it's just a slight glow it's not an issue. It just means that the slight capacitive leakage current that would normally be wasted is producing a small amount of light. With electronically active lamp where it makes them pulse it would be an issue.
So it's the snubber network that makes my GU10 LED lamps have a soft close on my dimmer for electronic transformer?
Clive, could you please make a video about driving triacs for use as switches and dimmers, and what typical practical circuits look like?
Huge undimmed fan of your videos!
Link to the bulbs that light up from the neutral when turned off???
Wander what the cumulative energy wastage of these leakage currents is.
You get the same if you use one of those switches with a small neon light for a CFL
+Andrei Marinescu I noticed this also on our newly built home. We have many light switches with the tiny neon light in them. LED bulbs are installed in almost all and they all flash. At first we were alarmed about it thinking something was wrong with the new wiring. A quick google search put our mind at ease. It is annoying none the less with blinking kitchen lights wile on a midnight snack run :-)
Our (new) place gets that, too. Some lamps also make an annoying faint clicking if you stand right under them when they're off. It's weird when you grow up thinking off means there's no way for power to run.
Ah, I made this comment about my garden lights before reading this comment. Anyway, snap.
I even got 'this without any dimmer or solid state relais. Even when the 230 volt led light is only connected by a mechanical lightswitch built in the walls of my house. Maybe some form of induction ? Here in the Netherlands wiring is put into pvc pipes wich are built in the walls and ceilings.Often you have several wires using the same pipe.
It's a common effect with some lamps. Capacitive coupling between switch wires is enough to make them glow slightly when off.