I know this is not an audio related topic, but I hope you can help me anyway, since it is about electronics after all ... 
The LED strip that I installed in a new kitchen cabinet blinks when the switch is off. The culprit is the neon, which allows a minimum current to pass that fluctuates depending on the network frequency.
Searching for info on the web, it seems that it is eliminated with a parallel capacitor, but I can't find how to calculate the value exactly. Some YT tutorials mention 0.47 mf. x 275 VAC, other 1 mf. x 400 VAC. I tried what I had at my disposal, 1.5 mf, x 250 VAC, polyester capacitor. It didn't give any results, so I looked for some more specific information, but all the manufacturers abound in the benefits of their products, but they don't provide that information, which seems to be a state secret kept under seven keys. I imagine there must be a way to calculate it according to the frequency of the network and the voltage, here we have 50 Hz and 220 volts. But it seems that these modern luminaires work with DC or AC, I imagine that the one installed is AC, from the looks of it, it does not seem to include a rectifier and it should indicate it if so...
P.S:
I don't want to override the neon indicator light, it's useful for quickly locating the switch in the dark.
Thanks in advance !
The LED strip that I installed in a new kitchen cabinet blinks when the switch is off. The culprit is the neon, which allows a minimum current to pass that fluctuates depending on the network frequency.
Searching for info on the web, it seems that it is eliminated with a parallel capacitor, but I can't find how to calculate the value exactly. Some YT tutorials mention 0.47 mf. x 275 VAC, other 1 mf. x 400 VAC. I tried what I had at my disposal, 1.5 mf, x 250 VAC, polyester capacitor. It didn't give any results, so I looked for some more specific information, but all the manufacturers abound in the benefits of their products, but they don't provide that information, which seems to be a state secret kept under seven keys. I imagine there must be a way to calculate it according to the frequency of the network and the voltage, here we have 50 Hz and 220 volts. But it seems that these modern luminaires work with DC or AC, I imagine that the one installed is AC, from the looks of it, it does not seem to include a rectifier and it should indicate it if so...
P.S:
I don't want to override the neon indicator light, it's useful for quickly locating the switch in the dark.
Thanks in advance !
Attachments
To really calculate it, you would need to know at what voltage the LED lamp starts and what the value of the series resistor of the neon lamp is. Using some rough estimates, 1.5 microfarad should be more than enough, though. With a 220 kohm or so neon lamp series resistor, it should be sufficient to reduce the voltage across the LED lamp to about 2 V RMS, far too low for any normal LED lamp.
If it's not a neon lamp but something that rectifies, then no capacitor can solve the problem.
If it is a neon lamp, but for whatever reason, its voltage drop in one direction is substantially different from the opposite direction, it could also be that the capacitor won't help.
Connecting an incandescant lamp or halogen lamp in parallel with the LED light could also do the trick, even if there is something rectifying in the neon or whatever it may be light.
We had a rather similar issue in a local radio studio some years ago. An on air LED light blinked when no one was on air. It turned out to be the current through the snubber of a TRIAC circuit that switched the on air lights, it was large enough to slowly charge the power supply smoothing capacitor of the LED light until it started up, lit up for a fraction of a second and discharged the capacitor in the process. I solved it with a shunt resistor, before realizing that a small incandescant lamp would have been more efficient.
If it's not a neon lamp but something that rectifies, then no capacitor can solve the problem.
If it is a neon lamp, but for whatever reason, its voltage drop in one direction is substantially different from the opposite direction, it could also be that the capacitor won't help.
Connecting an incandescant lamp or halogen lamp in parallel with the LED light could also do the trick, even if there is something rectifying in the neon or whatever it may be light.
We had a rather similar issue in a local radio studio some years ago. An on air LED light blinked when no one was on air. It turned out to be the current through the snubber of a TRIAC circuit that switched the on air lights, it was large enough to slowly charge the power supply smoothing capacitor of the LED light until it started up, lit up for a fraction of a second and discharged the capacitor in the process. I solved it with a shunt resistor, before realizing that a small incandescant lamp would have been more efficient.
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The usual R-C network is 390 k / 185 to 400 kpF or J / 440 V capacitor, to power LED strings and rechargeable torches. That is rectified by a 4 diode or single bridge, and a ripple filter of 100 to 470 uF is used, as per load.
Nothing secret about it, a quick search will give thousands of results.
If you want to be fussy, get a proper linear supply, use a regulator, SMPS may give noise to your fancy audio system.
In place of the neon lamp, use LED with 150 K in series, with a 1N4007 on the other leg...you can start with 22 k, but those heat up, life is less. Flickering solved, for dirt cheap price...5 cents here for the three items in sum!
Nothing secret about it, a quick search will give thousands of results.
If you want to be fussy, get a proper linear supply, use a regulator, SMPS may give noise to your fancy audio system.
In place of the neon lamp, use LED with 150 K in series, with a 1N4007 on the other leg...you can start with 22 k, but those heat up, life is less. Flickering solved, for dirt cheap price...5 cents here for the three items in sum!
Sorry, but I have no idea what you mean. Where does the 22 kohm go and why would an LED with a shunt diode and a 150 kohm series resistor (if that is what you are proposing) be any better than a neon lamp with a 220 kohm or so series resistor?
@academia50 If you have a multimeter with a 600 V DC voltage range, with the switch off, you could measure whether you see a DC voltage build up across the mains input of the LED lamp and drop again when it flashes. If that's the case, there must be some rectifying effect going on somewhere that causes the capacitor not to help. If this is the case, then, as far as possible, could you try to read off the voltage you get just before the flash?
If all you are looking for is keeping the neon light as a locating marker for the switch, if the return wire is available in the switch, tie the neon to the return so the neon is always on. Takes the LED strip out of circuit completely when off then. Neon of course will be lit regardless of switch position. And you'll likely need to increase the resistor on the neon lamp since the series neon/resistor will now be full line voltage.
MarcelvdG 11.45 AM
I have these, which one would you use? Which one will have better protection if I select DC instead of AC and/or vice versa ?
Hansen 600 Volts DC / 600 Volts AC
M890G 1000 Volts DC / 750 Volts AC
I seem to remember that a capacitor in series with the (+) tip can prevent damage to the multimeter, but I don't remember the value and I don't want to divert the topic, unless someone knows/remembers it exactly and tells me !
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When you try to measure DC with the meter on AC or the other way around, it is unlikely to cause any damage as long as the range is high enough. That's why I would leave it in the 600 V range.
If you accidentally use a current or resistance measuring range or have the leads connected to the current inputs, then you will have damage when the switch is accidentally turned on. 220 V AC on a meter set to measure current or resistance is bound to cause serious damage.
For the measurement I suggested, I would use the analogue meter, set to 600 V DC, and check trice that it is indeed in the right range, that the leads are in the proper inputs and that the switch of the kitchen light is off before doing the measurement.
If you accidentally use a current or resistance measuring range or have the leads connected to the current inputs, then you will have damage when the switch is accidentally turned on. 220 V AC on a meter set to measure current or resistance is bound to cause serious damage.
For the measurement I suggested, I would use the analogue meter, set to 600 V DC, and check trice that it is indeed in the right range, that the leads are in the proper inputs and that the switch of the kitchen light is off before doing the measurement.
It's a possibility to do that, but there's little room to work in there, and I'll tell you that now, my wife, seeing me working in HER
kitchen, tells me to leave everything as it is because she doesn't mind the flickering. .So the new question would be:
Can the LED strip be damaged by this residual current? I don't think so, but, one can never be sure, although it is a Chinese trinket, after all...
I think adding a rectifier is not the solution, honestly speaking I'm almost sure this works with AC. If it were a DC Led´s
strip, the flickering wouldn't appear, right? If you find a link where the "state secret" is revealed to know the value of the capacitor that appears in the circuit diagram that I attached, (typical capacitor sold in electricity stores, not electronics, that is what you would have to do, go to them, I didn't think this would get so complicated, I was expecting a response like: That capacitor in the photo is used in Europe, (the page was from the Comunity Europe, and they have the same frequency and voltage as here, in Spain , i think) and is x Mf and x volts.....
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You have been very clear, thank you! I will do that if I get permission from WAF .....
Ops, it seems that I used this link to download the attachment, and it is from Argentina, and also near my home!!!
I will go to them, thank you all very much !
https://www.kaiserled.com.ar/producto/parpadeo-en-luminarias-led/
I will go to them, thank you all very much !
https://www.kaiserled.com.ar/producto/parpadeo-en-luminarias-led/
Having to finish repairing an amplifier, and many other things to do, I decided not to waste any more time. The problem is solved, there is no more flickering. My wife had to accept my decision because my argument was irrefutable: "It is proven that the flickering of LEDs affects plants, because they are constantly subjected to 50 Hz frequencies during the night!" And she is very proud that she is plant has flourished because of all the care and love she transmit to it !
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I meant replace the neon with LED indicator...all you want to do is see the switch in the dark.
This is a typical supply, no ties, off the net.
Different versions will see component value changes for voltage and current, the R-C network is used to step down AC, which is then rectified and filtered to get DC.
The basic layout stays the same.
https://www.researchgate.net/figure/Power-supply-circuit-of-LED_fig3_321129046
This is a typical supply, no ties, off the net.
Different versions will see component value changes for voltage and current, the R-C network is used to step down AC, which is then rectified and filtered to get DC.
The basic layout stays the same.
https://www.researchgate.net/figure/Power-supply-circuit-of-LED_fig3_321129046
Thanks, but as I already mentioned, the simple solution I wanted (connecting just a capacitor) did not work, and I also checked that the switch/neon was on the "hot" pole, (may be one of the causes of the flickering) and That's how it went. I have done all the electrical installation in my house personally, and it is my habit that the light switches always operate on the "live" one) which is not the "positive" one, as many confuse, since it is AC)
In addition, replacing the neon on the switch with an LED was too complex due to the little space available inside the box and the time it would take, cutting the light, etc. For easy problems, easy solutions, that's my motto.
Greetings
In addition, replacing the neon on the switch with an LED was too complex due to the little space available inside the box and the time it would take, cutting the light, etc. For easy problems, easy solutions, that's my motto.
Greetings
He has a neon indicator, which leaks current, causes LEDs to blink.
Neons are less reliable than LEDs. And they run about 70V, enough to cause induced voltage.
So a change might help.
And the LED flickering can be reduced by putting a Zener, maybe?
To limit the minimum volts in the supply, so the stray current from the neon is less of an issue.
Donkey solution...try exchanging L and N to the LED driver, might work if it is a switching design, or change the driver.
Neons are less reliable than LEDs. And they run about 70V, enough to cause induced voltage.
So a change might help.
And the LED flickering can be reduced by putting a Zener, maybe?
To limit the minimum volts in the supply, so the stray current from the neon is less of an issue.
Donkey solution...try exchanging L and N to the LED driver, might work if it is a switching design, or change the driver.