Only goes to show that even after 40+ years of being an electrical engineer, I can still learn something useful (from a guy in Scotland who says "wee" instead of "little" no less). My days aren't long enough to watch all of your videos. And yes, LEDs are like optical garlic/red wine/thyme/rosemary/dark chocolate... they make any project more interesting.
I know this article has been here for a while but am just now getting to it and very glad I have ! After watching this I dug out some of my power supplies to have a look inside and after checking with a meter....... I deposited two of them in file 13 ! Between RU-vid videos and the comments on them I have gained SO much knowledge ! ( with some discretion that is 😎)
+Del Lawrence LOL Trading Standards is the old Weights and Measures here in Australia. They are now called National Measurement Institute and caused that many problems for their workers that were policing the regulations they all left the job. So they now have no-one to do any policing. I spend 8 years working along side of them before the workers quit and I went to the funeral of 2 of them just prior to Xmas 2015. Only one that still works there is a chef from Canada and he was offered a supervisory position with no-one to supervise because they all left. Even the 2 that died left over 2 years ago.
Unfortunately Trading Standards can't open every parcel that comes over the border whether from China or anywhere else. They are really only responsible for what is traded in my case, in the UK. People choose to buy from abroad and don't realise the risks they are taking, I for one didn't until I was converted to Bigclive.com.
I have the US version of these. The big capacitor says "CL21" and below that it says "255J400V". The resistor across that capacitor is green brown yellow. The electrolytic capacitor on the low voltage side is 470uF, rated for 10V. Every year, we put these up, plug them in, and if they don't work, we reverse the polarity. So it appears they are not harmed by plugging them in backwards.
"I like anything that lights up." Having spent a good many years as a lighting designer, I do too. And I'm really impressed by the fact that they put that nice clear poly over the nice thin conductors in that zip cord wiring the strings. You could put those up on your house in the winter, plug them in with the capacitive dropper supply, and if it rains enough you might have this delightful neon effect. At least for a few minutes.
+EpicLPer Imagine a 9V battery connected to a mains wire. You still measure 9V across the battery, but if you measure between the battery terminals and ground it will be full mains voltage.
+bigclivedotcom Yeah but... How? I'm far too noobish to understand electrical stuff further than just volts and amps but I'm certainly interested as this is also critical info for home stuff ;)
+EpicLPer OK, try this description. Imagine a block one inch high representing a low voltage. If it is put on a table, it is still one inch high, but MUCH higher above the ground.
Ha ha B.Zing!! or OUCH!! in my local slang lol :-) The lights themselves seem really dam good, well worth the pennies :-D The cheap switchmode, i would not worry about too much, unless your names dave jones. The reactance based supply needs a hammer and the bin, Fookin bad!!. It makes an old transformer wallwart look high quality clive ha ha.
Hmmm, this video actually gave me an idea for an overvoltage protection incorporating just a zener and a relais🤔 Thanks for keeping me sharp on building my power supplies as safe as I can (get a classic transformer)😄
I can relate, anything dangerous is more exciting. I have a wonderful insect zapper with an AC mains voltage tripler circuit. It lives up to its reputation as a deathtrap... 660 V zap!
Yes but it is out of service after the bulb blew and I can't find a replacement. I did try to convert it to UV leds but they burn out after only a couple of weeks...
Late, but heartfelt, thanks! Mine weren't working at all. I had undone them from the transformer and put them back polarity reversed. Happily, I didn't fry anything. T H A N K S! Was driving me NUTS!
That LED under counter strip light I repaired uses a main capacitor dropper circuit, Which is weird because it was made by a known name brand. I think they chose it so they could keep the overall design slim and discrete and not have to use wall warts. Use a recycled Li-Ion cell out of a laptop battery if you want it to last longer
What is interesting is that here in North America, the old bulb style christmas lights used our mains voltage and if you touched the leads on a broken bulb, you would get zapped. The newer led styles still are mains voltage with some potted device in line. I can't imagine if those exist in your country.
By underdriving them you'd greatly increase their lifespan. It might even be worth modding those dicey PSUs to deliver a lower voltage (even using a bigger zener + heatsink arrangement - inefficient but the energy cost's peanuts). We have a few of these out the back (summer). They are durable (electrically) but the plastic casing do NOT last well in our "rather bright" Aussie summer sunshine . . .
Nice dodgy power supply!! Did I also see one of the lights had developed that fault due to a failed LED? Regarding shocking yourself, I have had 240V AC shocks (and never really learnt my lesson) and one 8kV DC shock from a very large capacitor (and learnt that lesson the 1st time round)
Anyone who designs a mains powered LV circuit without proper isolation should be considered a terrorist. That crap is death trap waiting to happen.. I just shudder every time you find something with this absolutely terrifyingly bad level of engineering. With how many supposedly legit power adapters we've had die in our house, I finally started ripping them apart.. you should honestly question what comes with your phone at this point (despite it having some isolation)
+XFolf There is no problem in non isolated power supplies, they are used lot of in different industries, they are perfectly legal (you can find them in toasters for example) only is problem if you try to pass non isolated power supply as isolated. Problems are people who think that all low voltage power supplies are safe and that is not true, isolated power supplies are clearly marked, if there no is no marking on it and if someone get shocked it is not power supply fault, it is operator error.
+Miloš Lazović Miloš, y You are correct, non isolated supplies are legal provided that they are incorporated in a product where the user cannot access any of the terminals. But it is never going to be a user or operator error regardless of any markings. Any live or non isolated circuit must only be accessible using tools such as a screwdriver. In normal use, NOTHING touchable by a finger should beat mains potential. There is a lot of technical data available in Standards for product designers to use as to maximum hole sizes in enclosures, what insulation must be used etc. etc. Non isolated supplies are OK only if nothing can be touched. This is the exact reason we have Standards... to make sure products are actually safe... even for people who don't read instructions.
rowifi You are right to some degree, non isolated power supplies are legal for use, but product which use it must be as whole meet standards if you want to declare it as safety extra-low voltage, but if you declare it as low voltage then it can "pass" (and there is some expectations for light equipment, but I dont know exact ones I never did anything which meet that requirements). I dont think this product is safe, but there is difference is it safe and if it meet standards, same as E27 socket for light bulbs is unsafe but meet standards (especially in places where is in use Europlug or any other non polarized plug is used)
+Miloš Lazović Yes, light sockets.. definitely meets a standard but isn't intrinsicly safe. Don't let people know, the EU will ban them and have us design a new one!☺
Actually these are quite appealing but they are not as waterproof as you might believe. I had a couple of tubes fill up with water after a rain but just took the cap off and dried them with WD-40 and they still worked. I didn't trust the supplied PS so I used a spare 4 port powered USB hub that had a "real" PS and it worked to power 10 sets. These have a very unique look and are a good departure from all of the common home improvement store holiday lights that everyone else uses.
Found two sets of these recently without the mains plug bit ,how would i get them working ,even just the strips individualy for an rc car project please help
I am one of those hobbyists that would strip these wires by teeth with the powersupply still plugged in... Low voltage anyway 🤓. Tanks for this lifesaving video.
i've noticed on some of these stringable types with transparent insulator is that one of the two wires tend to be copper coloured while the other is usually a silvery tin colour
I have four sets of these, the two smaller sets of 8 are OK and powered individually but my two larger sets are linked together and the first 3 are really dim and the rest don't even light up. what do you think the problem might be here?
So... When a capacitor is connected to an alternating current it acts somewhat like a resister. Which is how capacitative droppers work. This is happening because they do not conduct all the time, only when they are filling with charge. It is this inverse lag which creates the effect like a resister. You can determine how much current--therefore voltage--you get on the other side by choosing an appropriate size of capacitor.
@@bigclivedotcom Aha!!! I finally think I might be getting this. So, the actual voltage reduction is only in relation to before and after the capacitor--just as it would be with a real resister--however when you measure any part of that circuit to true external earth then you just get mains... Which is why the probe beeped?
these lights are driving me crazy, i bought 2 packs of ebay but the remote they sent me only has a mode button and a off button. the mode button doesnt seem to do anything or if it does i dont know. th eoff turns it off and the mode turns it on. so i started messing with the buttons and now one lasts 2 hours and the other lasts only 1 hour. somehow im messing with a timer but there is no instructions. the first day they lasted i think 4 hours. i daisy chained them and they only lasted a hour so i seperated them for more power and they are still on the same time. can anyone help me out
Ha might have guessed you'd have a video on these things, Just about to buy a set so was looking on YT to see what they shone like and you popped up..Uh oh I said lol. However, I'm confused... I see you calculate AND test these with the meter at 6.2 / 6.19v DC but then go on to say they could be a bit dangerous as they are "referenced" to mains voltage... What did I miss here exactly. still getting a set though :D :D
I've just watched this again and it occurred to me that if I was to go round your neck of the woods I would spot your house from miles away, It's the only house that has got it's own Aurora.
Just got some of these, mine came with a small white box as the power supply but inside was the dreaded capacitive dropper :( Mine were also faulty with bad solder joints on one of the input cables. I am going to jerry-rig these and replace the capacitive dropper with a 5V switching supply. They do seem to have improved in one area though; mine were almost impossible to get into as they'd hot-glued the ends in with some very strong hot snot.
Great video Clive. However, I don't understand from your circuit diagram, how you're picking up mains voltage at the lights. If AC goes into the bridge rectifier then full wave rectified DC should surely come out the other side? The way you've drawn it, I can't see how any mains voltage should be present after passing through the diode bridge. Please help me out!
+tasmedic the psu came with a 'euro' plug, it can be inserted either way, so in his schematic at 11:47 he wrote L and N but in reality they could just aswell switched positions depending on how the psu was inserted into socket. So, the death trap happens when the live wire sits at the position marked N in Clive's schematic. When that happens both wires from output are in essence LIVE within a volt or 6. Even if you could guarantee that L and N hit their marks it's still a very dangerous circuit since some component malfunction or neutral wire coming loose means entire circuit is once again hoisted up riding on Live mains voltage.
Hey Clive, any update on your meteor shower tubes? Thanks to your tips in this video, I tested and marked the polarity on all of my sets. Now I'm trying out a 5.5v/1.5 amp power supply I took from an old string of the GE Color Effect RGB pixels). Using one of the GE power supplies, I was able to plug in all 10 sets and power all 80 meteor tubes. While the last 4 sets are a bit dimmer as the voltage starts dropping, they still look brighter than when I power 3 sets on one of the original power supplies. Do you see anything wrong with what I'm doing? My thinking is that it will be easier to only have 1 cord with 1 power connection (which IS waterproof and MUCH higher quality) as opposed to trying to use 5 of the original junk ones which are not waterproof and would require several of them to be used. Would appreciate your take on it.
I have a question, I have yet to use or understand the zener diode can as you say clamp a voltage to a set value, excluding heat of course I would believe there must be thermal ability value for size but if heat is for now taken as being no problem can you clamp say 7v dc down to 4v dc and keep it constant.
+gigabytex64 If you current limit it with a resistor and allow for the heat dissipation in the zener and resistor then yes it will provide a fairly constant voltage. I think the nearest to 4V is 3.9V. They're commonly used for low current supplies.
hey man when did green brown black become 510kohms?. Any way my question is about how much energy is wasted when those capacitive droppers are left hooked up to the outlet ?
Yeah I screwed up there. Theoretically a home electricity meter will not log apparent power, so at the moment capacitive droppers are a cheap and efficient way to run small loads.
Thank you for these entertaining and informative videos which reveal far-too-prevalent safety hazards associated with certain categories of imported products. The work you are doing is important and I hope that you will continue. I try to achieve a thorough understanding of your analysis to better appreciate the safety hazards that you uncover. Unless I misheard you, at 09:00 you read the cap-discharge-resistor colour bands as "green, brown, black" and decode that as 510 K. I understand the "510" but where did the x1000 multiplier come from? Did I miss something?
Did you ever get around to reverse engineering the power supply in the "safe" version? I'd be interested to see just what they left on the board and what was not added when it was turned into a PSU for the Meteor Lights.
@@bigclivedotcom So I should just leave them alone? Sorry Your comment didn't help me much. Thought there may be a way to trouble shoot it, but I'd better leave it alone unless you have a video that will help me. Thanks for your response.
Can you show us how to stop them from flashing ,I would Love to mount them horizontally and repurpose them as "steady" under cabinet type lighting ,thanks . Love your videos by the way .
I'm thinking about getting some for my balcony with a dark switch and supply them just enough volts so they light up to some visible level. It looks so much nicer than on full power for me. Just wondering how weather proof they really are, because i'm scared of heights.
what ic chip is used here?. i looked at other videos on how to make this but they used ic 555, ic 4017 and a transistor which circuit is quite big to feed inside this case. but here only one 8pin ic used. can any one what ic is this (5072B is written on the top of this chip)
Thank you Clive.. Is there a way to identify capacitive dropper power supplies vs isolated switchmode ones, without taking them apart? My floating switchmode power supplies display high ac voltages to ground, around 100v ac, though no current. No idea if that makes them 'dodgy'. Switchmode power supplies also trigger the non contact volt meter..
+CBC Poster The switchmodes in some of the LED lamps can drive quite high voltages for long series arrays of LEDs and may not be isolated from the mains. Some are semi-isolated and some are just buck regulators running at mains voltage. If you look at some of the lamp teardown videos on my channel you'll see there is a pattern to which lamps have capacitive droppers in them. Usually the lower wattage ones.
+bigclivedotcom I meant the wall-wart 12v dc rated power supplies. They have double-insulated symbols, but still show up to 100v ac voltage differential on the multimeter when referencing either + or - to earth.
+CBC Poster Ah, I thought you were talking about lighting. The capacitive dropper supplies are rare, but I think the best way to confirm is to open them up and take a look if they are not sealed. The switchmode supplies often do have a leakage current from the mains side coupled through a capacitor (see my video on power supply electric shocks) but these ones don't appear to have that capacitor.
+Stephen Lee I was expecting 1M (brown, black green) so made a bit of a derp that would have shown as a pop-up note on a suitable viewing platform. the actual resistor colour code was green, brown, yellow.
One wonders if there have been any casualties from these shock and safety hazardous power supplies. The thin wires with no UV protection due to the clear insulation means that after a few years to outdoor exposure it could have uninsulated wires, exposing the user to shock and fire hazard. Death lurks in the rain gutters. 😮😱😠
Clive, Love the video's keep them coming you make me smile. Do you have a link to the safe rather than deadly (beard on fire version) , or is it just a lottery Fergy x
I did accidentally plug a Chinese meteor light in the wrong way round for a short while and can report that nothing blew up (they're twinkling away as I write). Needless to say YMMV.
Ditto. Mine actually have a red steak down the wire, to indicate polarity. Unfortunately it's no consistent and has to change sides from time to time to work!
Hi Clive, I have watched many of your videos, and a few which ended up powering low voltage/current devices have been mains referenced when they take 240vAC, no isolation, through rectification and output low voltage/current DC to run something like these lamps. What is your consideration of a low cost but safe, isolated 240vAC to DC schematic design that us novices could construct inside one of these cheap PSU/USB style cases? I often hear you remark on filtering capacitors, opto isolators etc, is there a design you've done, or found, or even a product you've purchased that has the right amount of isolation/protection etc? Times have moved on for me from when a transformer was something you 'borrowed' from a old Spectrum 48k, lol! I've built up one of those 'Computer PSU's to workbench PSU', works really well, made so many LM317T variable voltage and 7805 or 7802 fixed regulators, but this video makes my heart miss a beat given I've just brought a set of the multicoloured meteor lights! haha!
Yep go for it Clive (Solar panel charging a phone battery) I made a light up fro my Chickens (long nights) running off a phone batt + solar cell and that was with 2 Super bright leds....Works well, I use an photo transistor to switch off/on for day/night but I never thought about running a string of "Meteor lights".......Nice
+Tayyab Naveed The one with the transformer makes an attempt to isolate the mains from the output. the one with the capacitor has the output connected directly to the mains with no proper isolation.
+bigclivedotcom In other words if one should chose the transformer if safety is the priority. what about efficiency which one is more efficient (in terms of keeping losses to a minimum)?
+Tayyab Naveed Yes, the transformer version is safer. Both have similar efficiencies, but the capacitor based one has a poor power factor (relationship between current and voltage) and may appear to be using a lot more power depending on how your power is metered.
You didn't consider the parallel 510k resistance (which I think was really 1M) in your computation. I know that it's >> than the reactance and shouldn't matter, but I didn't hear you mention that. why?
Wondered about that too, especially since I would expect the current to be higher then calculated with the extra conductance (parallel resistances calculate easy-er as conductances) ignored, and it turned out to be lower...
Didn't worry about the voltage drop across the bridge rectifier, either, but still got within +-20% or so of current. Actual capacitance might be a bit off 2.2uF, too. Questions were -- (A) will this light a bunch of LED strings and (B) will this kill you if you grab a wet bare wire with your bare feet in a muddy puddle if there were a high resistance to neutral? Yes and Yes.
Hi Clive looking to do your solar powered meteor project but had a look at this first and noted that my power supply was different again in that it has a small 4 pin chip marked MB10M. Sadly though no led in mine lol.
I wasn’t even aware that a simple dropper of any sort would be even considered in consumer electronics where the end user could potentially touch a wire.. (A self contained light bulb which screws into a mains socket-fair enough.).
Great job Clive, what do you know about Supercapacitors? I have replaced the battery in my scooter with them. At their price point. Would they be a good substitute for a lipo battery in photovoltaic charged circuit? I have heard that the Super Capacitors do not like to be frozen. That would be a problem for outside lights in Minnesota. Thank you again, :-)
+Willy Bee The way the capacitors work and their very low capacity compared to a lithium means they are only suited to specific applications. You can get solar lights with supercapacitors in them, but I've not tried one yet.
+bigclivedotcom I found 2.7 v 500 Farad caps on eBay. There is a RU-vid video where a guy used 6 in series for his auto. So I did the same thing for my Peagio scooter. And it works. There must be a drain in my system. If I don,t start the scooter in 5 days, I have to kick start it. The caps are the size of a D cell battery. . Thanks again for the reply. Ttfn. .. bill
+Willy Bee That's unfortunately one of the downsides of the super-capacitors. They have a high self-discharge. In the vehicle application they would be best suited to near-daily starting to keep the charge up.
+bigclivedotcom Thanks for the reply, the Internet is the new Ham Radio, Grand Dad would have crapped if he would have seen the Internet. Heck, when I went to college in 1980, they couldn't believe my predictions, then. Ttfn, bill
Interesting video.... I assume that another way of checking if your lights come with an unsafe transformer would be to put a multi meter across the positive output and a earth connection and if the voltage stays under 12v then its safe. If it raises to mains voltage ( 230v ) its not one of the safe ones..... is that correct ? ........ thanks ... I also like your repairing video... take care, Steve
That doesn't work. With a switch mode supply there will usually be a leakage current that can show as a high voltage on a standard high impedance meter.
@@bigclivedotcom so the only way we can work out if we have a cheap unsafe power supply with my lights is to take the power supply unit apart and look for the isolation transformer... Is there no other way.... Cheers
@@bigclivedotcom I'm not into electronics but I am an electrician and volt sticks are inaccurate. They will pick up induced voltage. For example in house wiring if the cables run side by side through joist you can pick up the induced voltage in a cable that's been completely isolated if using a volt stick but on touching the cable cores not get any great voltage... Not enough to cause shock anyway...
When I got this I was kinda dodgy about the link between the wallplug and powerblock. It weights almost nothing... with the idea it plugs directly to main.
+bigclivedotcom Is the tester that you've got a "real" expensive one, or cheap eBay kind? Bought one of these on eBay for about £1 and it actually detects the mains in wires and components, and stops detecting it when the mains is disconnected. However, it needs to be close up to register the mains, but it works. Wouldn't trust it though.
+Delightful Hardware If you've ever seen inside a "branded" voltage gradient detector you'll see that the circuitry is very simple with few variations. If anything I think I prefer the cheap plastic version to the metal barrelled "pro" one. Because poking around in a control panel with a metal rod isn't a great idea. I should also mention that these detector sticks are not infallible. So their use should be considered an extra step in testing for live circuitry.
Ok. I learned: Don't trust any unknown power supplies, buy a cheap USB one for 5$, they are built better. (They are really quite nice for 5$. Only up to 500mA, but that's why they are that cheap. I knew when those costed 35$, and now I can get 7 of them.)
+Michi Lo I had a cheap one that faulted then the output went live at full mains voltage. Many are not isolated and use around 7 or 9 components that can blow at any time. Get a decent supply. You own life may depend on how much you value it.
+bigclivedotcom so I was wondering is it possible with these capacitive droppers or resistive droppers to isolate the output from the mains, or is that the nature of the beast? You should make a couple of videos on building a better power supply. I must admit that I always thought you needed a transformer and/or switching circuit, to get mains down to low voltages before I started watching you videos.
Could you remove the end plug and replace with a male usb, Then use a usb mains adapter, one of the little white generic ones? (seem generally okay) and run 3-5 sets off of the 5v 500mA ? Skips the need to run on dodgy china frankenstein usb adapters id guess. Fantastic videos as always! Sam.
+Sam Canning Yes you could. But you have to be careful about the choice of USB adaptor, as some are just as dodgy as the switchmode one in the video. No proper safety isolation in the tiny transformer.
So -- If one were to take just the power supply, plug it in, and measure RMS current between either output lead and true ground, you'd see ~145 mA RMS AC? Which is well above the official trip current of any ground fault interrupter.
