I've noticed that a few LED bulbs continue to glow slightly, flicker or flash even though the power switch is off. This video explains why this happens.
Buy a more expensive brand - I tried one brand it flashed on switch off - tried another it glowed on switch off - tried a more expensive one - 2 bucks more - on switch off no flicker - no glow.
@@Mr21Franz My bulb is "Philips", lowest priced model. The reason it glows is, on the contrary to what most people think, is because the circuit is efficient, so much that even small voltages pass without much resistance. I think I will keep it.
Using the same process, you can make an oscillator out of a single transistor, a capacitor and a diode(or LED). Capacitor charges until the voltage is high enough to flow through the LED, discharges, and then repeats. You can even control the oscillation rate with a pot that controls how fast the capacitors charge, and you can tweak the oscillation frequency range by changing the capacitor value. The output is typically a triangle wave.
Nicely done, explained well even for laymen. As someone who had to talk to laymen about tech stuff I can recognize a well put explanation with examples. Cheers!
John my friend, your thumb was VERY close to that 110V. Sort of don't do what I do, do what I say. We don't want to loose you. Where I am it's 245V - OOER! Real tingle time.
Actually if the voltage is lower higher the amps, so a chock with 110 volt it feels way stronger than 220 I mean with the same power in watts, something that is 2200 watts of power working at 220 volts works at 10 amps, if you change the input and works at 110 volts, still go to work at 2200 watts, but with 20 amps, so the breaker,the wire and the amps running in that circuit will feel stronger because you feel the amp not the voltage....
You are brilliant! Spot on there! We never had issues like that with old Edison bulbs did we! LOL. Having a wall switch wired wrong is something that would have made no difference with a incandescent lamp. I learned about leakage when I tried using my old skool X-10 switch modules with CFL's several years ago. I'd turn the module off and the tube would still glow and flicker! Learned that the modules had a current bleeder that was used to manually turn on a lamp from it's switch without needing the command from the controller! So, now, if I use a CFL or LED on one of those modules, I have to make an internal mod to kill the bleeder so the bulb won't get the trickle current flow. Kinda tricky. Again, very interesting!
Thanks a lot John! I have a toaster plugged in a switched socket that is also plugged in a wall outlet. I know it is unorthodox a bit but I wanted to be able to switch the toaster on and off since it has not a built-in switch. I realized that toaster's LED indicator stayed on dimly when I switched the socket off. But when I turned the dial to increase heat (increasing resistance in a way) while the switch was off, the LED went off. While I was searching for the reasons of this issue, I came across this video and when I heard capacitive coupling, I tried to turn the socket 180° and plugged it in (an European wall outlet) again to tackle this phenomenon. Guess what... It worked :) I think because of wiring in that socket, the switch was located on the neutral wire. Turning the socket caused the switch to be on the hot wire. Thus, unlike the beginning, LED of the toaster stays off now when the socket's switch is also off. I am not sure if my approach is the exact solution for my case but hope it helps who has a similar problem. I would like to hear from the experts and broaden my electrical knowledge :)
I found 2 problems that cause this. No ground on the circuit causing the neutral to act as a ground which neutrals are technically grounds but a 2nd ground absorbs all the neutral feedback bleed power. And 2 the cheaper led bulb manufacturer making dimmer compatible bulbs never added a bleed circuit resistor around the triac which any little voltage detected can switch the triac gate on and cause the bulbs circuit triac to be permanetley closed and then glow from the small voltage feedback from the neutral since triacs are used in dimmer compatible bulbs and accept voltage from both directions.
You are correct I had a service call that had this issue the led bulb in a bedroom would glow after turning off the switch,the fix was the circuit supplying power was also tied into the smoke alarms and they didn’t make up the grounds in one of the boxes so it was causing the slightest voltage to back feed on the ground around 4volts
Very interesting video. I have a bathroom fixture with three Philips flat style 60Watt dimmable light bulbs. If I unscrew one bulb out of the three the other two stay on and won’t turn off but they are quite bright still, it’s really weird. I hope the leakage current isn’t costing me on the meter to the house. The outside light fixture on the garage was a 70Watt sodium light with a ballast and I just screwed in a cheap LED bulb to replace the sodium lamp and it works very well.
wow this is one cool video! i've always wondered why those leds do that. I especially loved the part where it lit up under the power transmission lines! very cool. reminds me of Nikola Tesla lol.
"Frank, come look at this... Our neighbor is doing something with a video camera. pointing a wired stick at the power lines." "That's nothing. His wife told me she found him hunched over in a dark laundry room by his dryer, muttering something about capacity couples..." I'm just glad you didn't yammer on about free energy and Tesla.
I prefer incandescent bulbs, I just like the light better, but I recently ran out and had to put an LED bulb in my bedroom, I shut the light out and it does not shut off completely like you say but also when I wake up 4 hours later it still has a glow. I can check the wiring but is there an easy way to stop this? I've also heard LED bulbs aren't good for you...thanks
Hi John! Thank you so much for this video. It now explaines why my IKEA-LED lightbulb was flashing when i hooked it up to my remote-controlled switch WHEN IT WAS SWITCHED OFF. (Here in Amsterdam, it's 230 V 50 Hz, btw). It's a switch that you plug in the socket and then it has a socket by itself and you can dim or switch it by a remote. I really thought that it was a complete switch-off, but appearently it is not the case. Also thank you for the video-bit of 'stealing' current from the high voltage live-wires. As a kid, me and my grandpa were fantasizing about a coil made up of wire and a drum. You showed me it actually works!
What you say is correct, but there is another reason why these bulbs will glow a while after turning off. If the glow dims over several minutes and finally goes out after turning off it is because the white bulbs use a blue LED with a fluorescent coating to convert some of the blue to green and red to get white just like fluorescent bulbs do. This fluorescent coating also has some phosphor properties, where energy is absorbed but not emitted immediately. This energy keeps the phosphor in an excited state for some short time, and as it decays off emits light.
Solved my problem. Thanks so much, man! Installed an outdoor flood light. When I turned it off, there was still some glow to it. Not good. Swapped the white for the black wire in the switch and it works perfectly now. Who knew....? Great explanation here. Thanks.
Hey, I use this feature for a night light in the hallway. Just put a .001uF across the light switch terminals. Costs next to nothing to run it all the time and have a regular light when needed. It is getting harder to find these lights without an inverter inside even at just $1. The inverter ones flash with this or don't light at all.
What he's done is add an antenna to the open circuit so the current isn't leaking it's turning into a radio signal. The glow is caused not by improper wiring in most cases it's just residual current that's present in the neutral loop due to other devices like fridges and clocks being on . The back feed of this residual voltage causes the lights to glow because the active wire is acting like an antenna and turning it into radio waves. Placing an antenna under power lines is doing the opposite turning radio waves back into power it's how radio and TVs works.
My blinking led bulbs are on a 3-way circuit with 2 wall switches, so not sure there is a good way to reduce the microvoltage induced into the open lines. Funny thing is they did not originally blink when they were first installed, only about 6 months later. No changes to the house wiring have been made.
Fascinating. I've wondered why one of the LED units in my home did that. I don't know much about electrical workings, but in my infantile understanding I figured it was something like this. I enjoyed the part with the outdoor transmission line. Thanks!!!
One time I helped someone put up their Christmas lights and a bunch of the led lightsets glowed like this while unplugged. I think I even got a small shock. I didn't know what the heck was going on until now. Perhaps that person's house had bad wiring with hot neutrals a long her house.
9:00 You are a brave man. "Standing here under the 240,000 watt lines" Holding a lightning rod in your hand. Thank you for risking your life for science, but we would like more videos, too! ;-)
Thank you. I came downstairs in the dark tonight and my reading light on my lamp was blinking, with the switch and lamp both turned off. I was ready to preform an exorcism on the lamp until I found this.
I have a light I made using an ordinary fluorescent tube and the circuit out of a CFL bulb, it works well but would be very slightly "on" when it was turned off, but when I reversed the live an neutral wires it stopped that and works as it should.
This have happened to me with a two way switch circuit. The (cheapo) led lamps were flashing slightly with some seconds period, a bit scary in a bedroom at nighttime!
Had similar problems caused by a control switch back box being too small, causing the wire insulation to be pinched and compromised. Remedied by refitting a deeper back box and insulation sleeving on the damaged wires.
Gimmick Loop This is a simple form of the capacitive coupling achieved using two closely spaced wire strands to provide coupling in order of picofarads between the two conductors. These wires may be twisted for physical/mechanical stability. Parasitic Capacitive Coupling This is an unintended coupling that may develop due to capacitance between two PCB traces or wires that are close to each other. This may capacitively couple a signal to another and give rise to unnecessary noise or interference. This can be avoided by maintaining safe spacing between the wires and other conductors, or running ground planes and ground lines between signals that are likely to interfere with each other. Capacitive coupling is used in a wide range of circuits to pass the required ac signals or desired frequency signals and leave out the undesired dc signal. Typical applications include: Amplifier and audio circuits Digital circuits Telecommunication circuits Cross-over and filter circuits Power supply units
Could you please tell me what did you exactly do to fix it? I have a fixture with remote control and when I turn it off with the remote it is still glowing a little bit, but when I switch it off from the wall switch it goes off completely.
What about LED light strips? Mine did not glow at first but they fell so I stuck them back to the wall and now they glow dim red when off ( remote controlled)
Today I just noticed for the first time that my Car LED bars (behind the grill) glow whenever I use them, and then turn them off. I figured it was only trickling out the final few "drops" of current in the wiring. Sure enough, they both glow ever so slightly (in the dark). After a minute or so, they no longer glow. The glow is so dim that I can barely see it in even the pitch darkness of night. Not bothering with installing relays, or troubleshooting my brains out. I'll just keep an eye on them for a few weeks and see...Otherwise, I'll take 45 seconds to disconnect the current and leave it that way until I truly (and rarely) actually need the extra lights.
ok, but, why did my LED's glow dimly during the 'great texas power outage' in February 2021? Those little LED nightlights, well, they glowed during the outage(s). If the power company shuts down the local circuit, why are my LED's glowing?
Thank you! I've often wondered about this phenomenon. Can you explain why a lamp with 8 small bulbs only works if I insert up to 7 LEDs and leave one halogen bulb, but won't work if I replace all of the halogen bulbs with LEDs? I suspect it must have something to do with the resistance. The switch is a simple on/off switch, not a dimmer.
David, Is this a low voltage (12v) lamp assembly ? Is there a PSU connected to, or built-into the assembly ? If-so I would bet on that PSU being a switch-mode unit that was originally designed specifically to drive halogen bulbs. It would then need to see a proper load from the halogen bulb(s) before operating correctly. LED units do not "look" the same when you put a multimeter across them. Once the PSU "sees" the halogen bulbs's resistance/load across it, it will develop the full 12v and hence the LED bulbs will also light-up in parallel with the halogen bulb. The cure for this, so that you can use all LED units in the assembly, is to change the PSU for one specifically designed to drive LED units. Some PSUs available will drive both LEDs or halogens. Obviously that may only be possible if the PSU is separate to the lamp assembly due to size and shape limitations. If the lamp assembly you have is not low voltage (12v) and uses mains voltage LEDs and halogen bulbs, I cannot then offer an explanation. Rob.
So how does this happen with a rechargable battery LED light? I have a rechargable light that flickers often after being USB charged and unplugged. Is this a sign of the light starting to fail? Not a big deal but I was just wondering.
I had an LED bulb go 'bad' recently. When turned on, it was very dim, but on. When I unscrewed it to replace it, it remained lit for approx. 5 seconds after being fully removed from the socket. Assuming this must have been residual current stored in the capacitor?
I believe when you connect the extra non-charged wire to the LED, it is actually converting radio waves into enough power to charge the capacitor then provides just enough power to light the bulbs slightly......try turning off ALL electronics in your house that uses a radio signal including unplugging your Wi-Fi, then try the bare wire test......or try putting the wire only in a faraday cage....that may make the difference!!
That capacitive coupling (happens to LED in refrigerators too that was originally using an incandescent one- what's the solution for that btw?) it's like induction in wireless charging I think. God bless, Rev. 21:4
Anyone has any answers to why the LED summoned that bifrost at 0:55 instead of the usual flickering on the screen? Why did the camera captured it like that? Please I want to know what's going on
Curious about that bulb as I don't see a smoothing capacitor or a bleed resistor. As the bulb is coloured I don't know whether it is designed to be used with triac controllers such as sound into light modulators.
What happens of that happens with lights that aren't LED's? Also what happens if it stops in one place and starts in another? Example: moving into a new apt and having it happen there and stop at the old apt?
No idea why they would even make a colored LED bulb with the phosphor coated "white leds" which are already blue without the phosphor. Seems kinda wasteful to me as phosphor does cause slight efficiency losses
Nice video!!! I bought a rope light that has the same issue, the thing is that I have the stuff around the whole yard and it never turns completely off.... What resistor would I add to an led strip (the rope light) that's about 150ft long? I'm estimating 800W and on although I use a dimmer to make it not as bright. since it's an LED strip can I just bridge the positive and negative terminals at the end of it? ) - it does glow without the dimmer as well.. Thanks so much!
Is there any way to turn off an led that keeps glowing? Something like discharging it with a resistor or something? I got a problem with an led ring for selfies and haven't found the fix. Thanks for your video.
Hey @JohnAudioTech ! Thanks for this video. I learned that the switch on my lights is on the negative wire. Is there a way to fix it without having to switch to the hot wire? Installing the switch on the hot wire would imply cutting into the wall...
I have a ceiling fan with a built in 18 watt led light kit. No bulbs, just a light strip in it. When the light is off and we run the fan we are getting a very slight flicker to the light. It’s not bright. We have had the fan installed for a couple months but I just started noticing this. Is this ok?
you just need to make the Hot wire always go to the switches to avoid this ( when your connection type is Line to Neutral ). and when your connetion type is Line to Line just Connect the Switch Return to the Gold terminal of receptacle.
If there is switch on phase side, when switched off, then also CFL Build flashes some times why ? From where the bulb get current and how circuit is completed .
At my house, I have lights let up that you plug in, when unplugged there are sections that light up dimmly constantly. (Even days without being plugged in so it can't be the capacitor) wrapped around timber. feel like current leakage not the issues, maybe eddie current. only half of the circuit is along a 2.5A cable but it lights up(dimml) in sections. and parts have lightened up that are not near the cable. can anyone help? im an apprentice sparky so still fresh. EDIT. not under any powerlines.
I noticed this effect on my outdoor xmas tree tonight. The tree has an indoor plug, with built-in timer... 6 hours on and 18 hours off, with a very low voltage going to the outdoor xmas tree. It had been off for 3 hours, but some of the led lights had a dim glow. Is it faulty?
I have an LED floodlight that stays on for a little while after the power is turned off. It's in an outdoor floodlight in a motion activated light fixture. Bad discharge resistor in the bulb??
How long is "a little while"? The phosphor in a white LED can have an afterglow that last for a few seconds. Could also be the smoothing cap discharging. The discharge resistor won't have anything to do with it. Its resistance is usually picked so it discharges the cap over a few minutes (everything else would be a waste of power).
superdau it stays glowing (not fully) for maybe 5 seconds. I figured it would be a smoothing capacitor discharging and it stays glowing longer due to a bad bleed resistor.
I have bulbs they glow maybe 3 seconds and then dimmer for another few. I figure that is also why they never flicker even when set real low. On the other hand and have spotlight that never shut off until I moved it to another plug. I am not happy about that.
+JohnAudioTech - Dont forget induction etc. ... cable = antenna (also for by "Dirty electricity" produced EM-radiation & radiation from power-lines, transmitters etc )
Yesterday I swiched my house electric to 220 ,it was 110 before . Sinse every thing in market became for 220 in my country ,and also to use LED lights because some LED onse works only with220. But i found some of LED white bulbs keeping dim light. What should i do? I realy don't like thinking of electric leaking consumbtion and safety.
The glowing doesn't bother. My question is, is the glowing costing additional consumption cost. Is it going to cost me extra with the electric company?
I am laying in bed im dozing off and my room is almost lit up? I look at the ceiling fan and its light up! My switch was off . I GOT UP TURNING ON THE SWITCH , IT LIGHT UP ON NORMAL. THEN I turned it off . It dimmed this way for 3 or so minutes....I have never had this happen before?
We are leasing a house, after living in this house for about a year. In the kitchen there are four pocket lights (older house, so pockets were supposed to be an upgrade I guess). We noticed a kitchen pocket light burned out and then the other pocket light would not completely turn off.. when the light switch is in off position (no dimmers). I replaces all the lights and 3 worked, but one new light never worked.. but with 3 lights working, when I turn off light they all go off and stay off. I noticed tonight one of the 3 working lights burned out. Now when the light switch is in off position one light stays on (albeit dimly)... very puzzling and worry some. O' and the 4 pocket lights are controlled by two light switches. Landlord acts confused and just says replace all bulbs, but this has me worried, faulty wiring for poorly installed pocket lights. I have no idea what kind of lighting was in that kitchen before? The place has been cheaply renovated, by looking at ceiling easy to tell where a wall was taken out and cheap wood flooring was poorly put in.. open gaps flooring doesn't meet wall very well in numerous places. Anyway, ya any idea how worried I should be about the wiring with these pocket lights? Anyone
This is one of those videos that slightly make me a bit terrified of electricity because sometimes it does some weird shit like randomly being able to dimly light lights through the air. At the same time, it is fascinating. It's basically why Tesla wanted to create a Tower that basically dispenses electricity all over the globe because it's possible for electricity to travel without a wire. Although, on a large scale like what he had in mind, we aren't close to having the technology to be able to regulate the amount of energy to do that. Basically, I think if we tried to do it now, the ones closer to the tower may have their electronics explode while others that are in the right distance get a good charge. Any further and the charge is slow as hell. Plus, for example, phones work on 5v DC, appliances work on 120-220. There is so many problems with the idea. I think I went on a pointless rant but this video makes me think of this type of shit.
Naseem Mohamed I wouldn't say it's pointless at all; people take so much for granted, and don't really realize what is going on. FWIW, molecules are COMPLETELY reliant upon electric charge; seems it's all about electric charge.
I'm having a similar issue in an car. I replaced some small driving lights (factory ) with LEDs and they glow dimly when off. I just installed them so I don't know yet if there will be any power drain. We'll see..
I recently bought a new home and switched all my lights to led bulbs. A few of the hallway bulbs dimly glow when the power switch is off. They are not on dimmer switches. My question is, is there are fire hazard?
No they are fine. Without getting into all the details, there are several reasons this can happen and none are indicators of fire hazard. If you do have switch on neutral you have a safety issue but its not a fire hazard issue.
@@helloimbasa Neutrals, which are in the category of grounded conductors are not allowed to be switched, per NEC in the US and likely in most other sane countries as well. Basically if the neutral is switched then its possible that all sorts of situations can occur where the device(s) and conductors are hot up to the point of the switch. Imagine having a switched outlet in a room and the switch is on the neutral. With this configuration the device is hot and both conductors are hot up to the switch. Someone could literally think the device is safe because it is switched off and do something dangerous, possibly even purposefully.
Hello folks so i have a sensor solar light that is doing that glow ones it turns off but i noticed that if i turn off the switch from inside it completely turns off what might b the issue any ideas
What about on a transistor radio? Tuning LED on my c.1980 Panasonic AM/FM/SW radio.... While switched off.. Draining batteries after a few days... J.C.
Is this necessarily a problem? I have led strips on my desk, whenever I turn it off, there is always a dim glow. Only when I unplug the power cable it stops emitting light. My question is, do I have to unplug the power cable every time I’m not using the led? Or can I just leave it as it is, will the slight glow course any damage on the LED?
