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High power ultraviolet LED experiments
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- Опубліковано 24 січ 2024
- Some experiments to see how a selection of series capacitors affects the power dissipation and output of a 50W near-ultraviolet LED.
The small motor-run capacitors look very promising for reducing the heat dissipation and extending the LED lifespan of these LED modules. Be aware that these capacitors do not have discharge resistors and can deliver a zing, so a couple of 470K resistors in series across the capacitor is a good idea to drop the voltage fairly quickly.
With standard LED floodlights the capacitors could either be mounted internally, or in an external box. This could be an interesting way to prolong the life of external security lights.
All tests were done with a 240V supply. For 120V use the capacitor values will have to be higher.
I Have no way to test the wavelength accuracy.
The gloves I wore in the video are standard half-dipped work gloves. They are not officially rated for live electrical work, but do provide a secondary layer of protection against shock at mains voltage. If working in a wet or outdoor environment take extra safety precautions.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- www.bigclive.com/coffee.htm
This also keeps the channel independent of UA-cam's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
The tip of the index finger is missing because that’s Clive’s capacitor discharge tool.
So I started the video then skipped ahead after reading your post, and it literally landed on that exact moment.
I'm wondering if the actual tip of Clive's finger is from Temu?
🤣
@@AndrewJensIt came in a handy 5-pack.
Clearly a deliberate removal, a smartphone operation modification, perhaps.
3:37 "an extra layer of protection" missing a finger on the glove. 😆Never change Clive! Your humor brightens my day often. Cheers.
Me too :-)
Yes Clive, never change... 👍🇮🇪🙏
"At this point you could skip to the end and see the results."
No way! Great video!
When curing UV resin, I’ve found less intensity for a longer duration gives a nicer finish. It results in less heating and therefore less stress / deformation as it cures. A gradual increase in intensity as it cures seems ideal. Although it can be blasted quickly if it’s something which doesn’t require a nice finish! 🤓
Can confirm it cures shinier, also a shorter wavelength helps cure it more uniformly 365nm is the best, but 395 would be good for thicker resins.
Yes, the shorter the wavelength is better for surface cure. For surface curing, Oxygen hinders surface cure. "Oxygen inhibition"
That’s also very good to know, thanks!
Like making custard. 😅 To much heat😮 and it's wrecked 😅
Yep. It's akin to having a paint booth temperature up too high when curing the paint.
If the uv resin cures too fast, the surface of it can cure before the rest of it underneath does, and when the rest of it cures, it can shrink up the surface and leave a less than desirable finish.
I've missed these kinds of experiment videos...not to mention the useful knowledge imparted :)
The great thing about using a capacitor dropper is the VERY low thermal dissipation. They don't get at all warm, and for the 50 or 60Hz mains frequency, the stresses on the dielectric are also pretty minimal. The only downside is the power factor, but for low power applications that's probably not a serious consideration.
I agree... the .5 P.F. is nothing to be concerned about with a few watts. 👍
Dubai'd pretty nicely, and the measurements clearly show a linear relationship between capacitance and power. Good work!
Thanks, Clive. I’ve learned so much from you over the years; your manner of teaching is what I wish I had in school all along.
Me too :-)
I would have loved to have had a teacher as good as Clive(and others here on UA-cam) wish I learnt electronics when I was a kid... My life would have turned out brighter (pun intended)😅
I had one of these a long while back I thought wow how brilliant is that, then I remembered how thin my curtains are, and it must seem like I've started a grow lab 🙈 so rather than be raided at 3am I decided it would stay off and look pretty instead 😂
My play with such LEDs succeed by resoldering a current control resistor to shift down power and add a capacitor after rectifier to get rid of flickering.
For white 4000k leds it is a great solution!
Low heat, no fan needed, long life, no flickering, hotter light temp (makes 3000k from 4000k). Ideal!
You should create a decade capacitor box using standard values as steps instead of 1, 2, 3, etc, with discharge resistors across each capacitor and an on/off switch for preventing arcing will changing the capacitor. Maybe an extra push button in parallel with the on/off switch for fast testing? It will be an interesting project video!
While borrowing the decade box layout from the one Dave tore apart a couple months back
If you read УХО in Russian Cyrillic it means "EAR", can't unsee it as soon as I noticed the logo.
That's got me thinking about mounting one to light the street outside for Halloween.
Clive, I would never skip ahead on any of your videos. It's all interesting. Plus I was hoping to get a little suntan while watching.
I have LEDs from this company and the resistors under the silicone rubber were very easy to replace 😊
Thanks Clive, a very useful experiment, great idea to use the load capacitors
In order to optimize heat dissipation and operating life, it's still better to run the LEDs at a lower *peak* current. Series capacitors only reduce the average current and do not reach the same efficiency. For reference in my office at work I tried multiple LED blocks like your yellow one: 50,40,30 and 20W. They were all exactly the same with a different number of regulators soldered on them, so all that changes is the current through the LED. The 50W one lasted one week, the 40W one month, the 30W ~6 months and the 20W is still working fine after 3 years. And the luminous power is not that far from the 50W one, probably about 2/3 of it. So the best way to achieve optimal efficiency with LEDs is just to buy the lowest power modules of the same family and install several of them in parallel if needed.
Cheers Clive. Interesting results and well worth taking note of.
"Violet is turning Violet !!! "
willy Wonka:" Don't worry ,its just big Clive doing an experiment with a high power U.V LED nearby.....
Thanks Clive, this info is good to know! 😀👍
Nice explanation as always Clive 👍
A rotary switch for dimming sounds like a good idea. High low and off, like a box fan switch. Thanks, keep working.
Amazing!!! Thankyou for your efforts!!! For the last few years I've been using 12 volt LEDs to help my tomato plants grow through febuary and March. this year I'm upgrading to the supercheap LED grow lights. I did a few grow tests with chili peppers, and I'm impressed with their results for the price!
Excellent experiment Clive nice results thank you 😊
Excellent demo of the role capacitors have in dropping power. Often refered too but rarely seen like this. Cheers Clive 👍
Air conditioners usually have two capacitors in the same can. They never fail together. I have a half dead one reducing the brightness of an incandescent four channel sparkle/chase light set on my house. 🎵 Making good use of the things that we find, things that the everyday folk leave behind. 🎵
Great experiment Clive. The 2 or 4 uF motor caps are excellent for the reduced power dissipation in the UV LED chips. Love the missing tip on your "safety glove".
I tested a Motor Capacitor with my insulation tester set at 250 v, then discharged it at arms length with a screwdriver, what a loud bang it made, I chickened out trying it at 500v or 1,000v, as I thought it might shoot off and break something.
It's also not so healthy for the caps
Thanks Clive! I will always keep an extra layer of protection around if I need it.
Can't wait for you to upload your videos Clive, you're a legend!!!
Clive goes all "Prudence The Safety Goat" with the gloves.
Also Clive: puts on gloves that are missing a finger.
That's why I watch.
Only the best videos start out with "I have a purple LED..." 😁
I've been investigating UV LED for a while now; putting together a water purification rig that can support a few people while camping, so need some decent volume/flow but that limits the time the water is exposed if it's moving fast, etc, etc just another use case but having someone put all this tested data here is pretty great to use.
Thanks man!
For water it will have to be UVC, and at this point in time the best source for water purification is still a quartz tube mercury vapour version.
Now Clive goes into work wearing a sunburnt face with a hand shaped white spot.
Great test, Clive. I'm glad to have not skipped to the results when there was a chance you got zapped, but the small crack was sufficient with the screwdriver. I am evil, yes I am, lol.
A nice experiment!
Awesome experiment and useful too :)
You know things get serious when Clive brings out the gloves
Interesting light driven at a lower input will save the LEDs frying.
I would love to see just how they make both the bear LEDs and solder them to a board. (your cue to fly to China 🤣🤣) See you Thursdays Live Patron. 2x👍
I've recently fitted a capacitive dropper circuit to a valve heater chain in a Bush DAC90A radio I have. So only a small portion of the original dropper resistor is used to feed the rectifier valve anode. The resistor is now running cold and the heaters are at around 5.6v AC - a little lower than they should be but with no or little detriment to performance. I'm using a 10 Ohms 1 watt inrush resistor and a 100K 1 Watt discharge resistor across the 1.5uF 400V AC rated motor capacitor. Using phase-shift to reduce power output rocks, my wireless now no longer smells of hot dropper resistor and the case isn't being slowly cooked.
I'm a great fan of DAC 90A radios and have a fine collection. Really looking forward to trying your dropper idea! Thanks.
At 4UF is even half its full power so it will last years more. Great video.
I am using these LEDs for developing cyanotype photography, and I bought these about a year ago. Bought 4, using one so far to expose cyanotype coated papers.
Now with these capacitor hacks, I might have to start messing with the LED (which I planned for any way hence purchasing a few!)
I did also ground the heat sink to be extra sure
Now that's a good coincidence , yesterday I ordered that exact dob led board from AliExpress... I suspect I'll be adding a motor cap now...👍
😊 as always, it is very fascinating
Boy, the manufacturer of that LED COB must REALLY have their reflow profile down to exacting specs and tight control to be able to produce those flip-chip COB's without having a ton of "tombstoned" or crooked LEDs that are only contacting one of the pads.
It's amazing what the surface tension of liquid solder will do to a tiny part like those individual LEDs if only one of the solder pads has it's solder paste melt first.
The reflow profile MUST be so closely controlled so that ALL of the solder paste turns to liquid at the very same time. Back in the day when we didn't have such precise control available, the SMD parts were glued to the board with tiny glue dots placed by a machine before the pick and place machine put the parts on the board.
I can't imagine that those tiny LEDs are even able to be glued down.
It sure has to be hard to control the reflow process with today's lead free solder too... 😬
That's one heck of a SAD lamp, Clive! Mandatory sun screen and shades must be worn though... 😊
We're going to test that.
i actually have one of these, but with a pink light meant for growing plants
i modified mine by removing the ptc and placing a 10k pot in it's place, that regulates the brightness really well without having to get a dimmer or finding a suitable capacitor
I used to use gloves just like that all of the time for 120 VAC work all of the time.
395nm is my favorite nm. Love that deep purple glow. I light up my entire house with it.
I am now going to use THIS video every time I need to explain the concept of a current limiting capacitor to someone.
Instant "like' the moment I saw High Power and UV in the same sentence!
Now, on to watch the video! Thanks Clive - I just KNOW this one will contain a reference to a Death Beam(tm) of some sorts...🤣
A good video! I can extend the life of my LED grow ligths this way...
Thanks.
Clive. Given you said LEDs you've reminded me that I was going to send you a link to a video that is making LEDs. You'll find it interesting. 😄👍
As a novice electrical engineer wanabe, this was a nice video and helped me understand something that was seemingly complicated prior. Anyways, i need that handy tool you got there. I type too fast on this small keyboard....Fixed grammatical errors.
Make some with your config and sell them on the side . It could mean extra Guinness of the shelf ! You may have started a fashion craze with the gloves . One must be careful about such things . Thanks for the share . :O)
Only drawback is the lack of smoothing on the LED module itself, driving people nuts who can see that flicker, though on the plus side, it coul dbe a good deterrent as part of a purple burglar alarm............ :P
even I had to look away jesus thats bright.
LM358? An op amp, a voltage source, a MOSFET, and a resistor are enough to make a current sink; an inductor, a diode, and some positive feedback added to that makes a hysteretic converter. I for one wouldn't mind seeing the teardown.
Too cool, as well.
The way to align those tiny chips on the solder pads would be to use a dedicated pick and place machine, but if I had to do it manually I'd use a stack of two photo-etched masks. One to provide spacing and avoid disturbing the solder paste, the other closely fitting the chips so they could be dropped in with small tweezers. Potentially a third one above this could provide guiding channels to slide the part on.
Thanks :)
I wonder what they are doing to those flip chips to permit soldering? When i took a semiconductor lab in college, we had a special weird solder, indium based IIRC, to solder to silicon, and it was a right royal 5 star PITA to get it to wet the surface.
It was a lot easier to use the special probes that just mashed into the surface with a rack& pinion setup similar to a microscope.
I think the LEDs have a metalised layer on the base for the connections.
At that scale surface tension is a usable force.
i have loved UV since attending a pantomime some 40 years ago. they did the thing where the lights went off, and a UV light flickered on and off so the 'skeletons' on stage appeared to run about madly fast. i seem to recall Christopher lilicrap was in it, and he sang a song about making 'a proper cup of coffee in a proper copper coffee pot'.
I had a similar UV skeleton experience at a pantomime at the King's Theatre in Glasgow when I was a kid.
Great fun Clive. Now I'm curious to see if there are similar 365 nm parts available...
Apparently UV curing is basically a matter of proportion of t*W/cm2. Reducing power to increase longevity would either increase time and/or require changing distance, both of which may be acceptable trade-offs depending on the application. Given that there are are exponential decreases in longevity with high junction temperature you could get a lot of bang-for-the-buck tuning the power usage of these devices rather than investing in cooling solutions.
Thanks
Thanks. Much appreciated.
A lot of great FAFO in today's video.
Let's be honest, we all watch Big Clive to see if anything goes "bang".
4:58 "that is making everything in the room glow" lol... wink wink xD
Something like a 5 or 6 position rotary switch and a hand full of caps would make a very simple crude dimmer for these.
All of the resin for 3D printing that I've seen, that is for the hobbyist, states that it cures using 405 nm UV light so that's what I thought the printers and curing stations were using.
As Nomad in Star Trek would say, ‘ STERELIZE’
For the touchscreen - beep boop boop😅😂
I used a great deal of UV in nondestructive testing, despite glasses with UV filter I am headed for cataract surgery.
You may just be unlucky. I have plastic eyes now. They are a semi-failure in that they were supposed to give some degree of accommodation (ability to focus) but I've wound up with absolutely fixed focus. Still, I'd be blind without, but I spent a lot of money for the "premium" implants and got no added benefit.
I wear the touchscreen version of those gloves. With all the finger tips
"As an electrical safety measure" Proceeds to wire up circuit with all wires the same colour and the live and neutral reversed. 🤣
I recently got a small LED keychain light from Aliexpress, not only does it come with red n blue flashing lights on the side of it lol and the entire case is glow in the dark, it also has an ACTUAL Black Light LED! the one that reacts to white objects and what not. I was quite surprised it came with an actual Working Black light/UV LED
These LEDs are also used inside the cheaper LCD resin printers as the main light source for the LCD. They tend to be much less reliable than SLA or DLP printers but are much cheaper.
If you want to make touchpad-enabled rubber gloves, you can get conductive yarn.
Unfortunately, we can't truly appreciate the brightness and color through the camera, but we can imagine that this much wattage at this wavelength must be a pretty impressive blacklight ;).
I have gloves like that for cleaning fish at the cabin (grey glove with blue coating), and even while dry, they allowed touchscreen use. _(modern smartphones, so capacitive; I don't own anything with resistive touch)_
seems to depend on the brand, im a mechanic so generally buy in bulk and simply buy from whosoever selling 120 pairs for cheapest on ebay or that. some work absolutely fine with a phone, some dont, in the latter case simply using your knuckle seems to do the job.
@@denisohbrien haha Yes... I've done the knuckle trick as well!
Albeit for different reasons, as the palm side was slathered in fish slime... 🥴
As mentioned in previous comments ... the CPC 2μF capacitor is IDEAL for those wanting to make an ( everlasting ! ) nightlight using a 230 Volt , 60 Watt " squirrel cage " Tungsten filament bulb ( our Poundland™ seems to have sold out ? ) .... but this lamp will then last longer than you do ( ? ) ... ( tried - n - tested ) ....... DAVE™🛑
Hi Clive. Interesting video. I actually bought the grow light version the other day. I was wondering what RCD should be used with them? Would Type A work or do you need a Type B?
Very good experiment. More like this would be nice.
Do you have any idea if the supposed 395 nm wavelength is harmful to the eyes?
The extreme ends of the spectrum pose a risk to eyes because they are seen as a "dark" colour and the eyes don't react as they would to white or green.
Did you notice Clive’s fingernails glowing at 8:23 when he added the 220 nF capacitor?
Any wavelength that excites fluorescence in biological materials like that is hazardous to the eyes at the very least. Shorter wavelengths can literally burn skin as I’m sure you know but longer wavelengths are still nothing to trifle with.
I have still never gotten over UV making nails and teeth glow. Very cool, but any anomaly like that should make you extra cautious.
@@markfergerson2145Intensity is everything
UVA is not yet a major risk but you want to avoid looking into it because our eyes dont see it very well. it is much brighter than you can see so you dont have the natural reflex of squinting and adjusting the iris.
Usually I modify these AC COBS with two parallel 1µF X-type as a dropper C and 25µF 400V electrolytic across the + and - of the FBR make these mostly flicker free and not run hot with basic cooling. It's quite hard to get a good solder connection tho - even with all silicone carefully scraped off.
Hi Clive. What do your bank notes look like under a UV light? would be interesting to see.
They have quite interesting patterns.
@@bigclivedotcom So did the ones in New Zealand before they changed to plastic notes here. now they just have a square with the note value on them . but have never seen a UK note under a black light.
3M sells good safety glasses that will protect you from that light.
It may leave you with yellowish spots all over if you get too high of an exposure.
I‘m interested in these LEDs but am looking for ones under 300nm.
Something changed in your microphone. I can hear metalic noise now.
Let’s face it if big Clive bought it it’s not ultraviolet it’s ultrahotpink 😂
Chip shooters when I worked on them were plus minus 60 microns placing at 16 a second
Brother I just want to say this again, as photonicinduction, tom scott and other youtubers that basically quit for human reasonable reasons ofc... would be huge disappointment if you did the same, I hope you don't plan on doing so anytime soon because that would be an addition of good content that teaches and motivates people in doing electronics / electrics being lost, I'm sure you understand your value and hope it continues so, I'm just afraid of good content creators that are also good teachers being lost over time, maybe I'm exagerating but it's meant will good intent, keep doing you, cheers! :)
No plans on quitting in the foreseeable future.
@@bigclivedotcom Awesome to hear :D
I always discharge caps the same way I "test" 9v batteries...on the tongue !. You can tell the charge by how loud I pop.
Looks useful, but I don't have a use for it!
The name means, " burns your retnas" in mandrin. 😂
I have one of the 70W light chips but blue-green for growing (just spring seedlings in my case), but it produces too much heat, even mounted to a big aluminum tube and using a diode to cut out half the cycle. I never thought of using a capacitor to limit the power, despite seeing a bunch of circuits doing it that you displayed. Wonder what higher voltage capacitors I've got kicking around.
perhaps the reason the capacitors did not hold much charge because they are connected in series with the leds, hence they hold low voltage?
The meter will have provided a slight current shunt in combination with the circuit's low current drain.
There are small test strips made and sold cheaply that can identify UV B and UV C etc. Depending upon the freq of the light (advertised or not) you should probably be shielding your eyes from it...
BigClive, when you do "experiments," do the mad scientist "mwuahahah" laugh!
For this to work, the LED board needs to be somewhat decent quality. I tried to limit a very cheap led projector like this, and it ended up powering only a quarter of the LEDs on the board, and it still failed after a year while also lowering the light output.
i wish i could say the fingertip of the glove was removed with scissors in safe manner before the gloves were worn, but something tells me i might be wrong.