Being someone who suffers from chronic cornea damage, I do not recommend potato juice. I am also not going to give medical advice but there are over the counter eye drops that will address swelling and pain without the risk of an eye infection. Great video either way, Clive. Thanks as always.
As someone who has suffered from weld flash a couple of times, the potato works. Just cut it in half and put each half on your eyes like you're relaxing at the spa. The first time I got hit, it was bad, and i tried the eye drops. They did nothing. I finally broke down and listened to the "old-timers." It was near instant relief. I felt silly doing it, but after spending a night, blind and in intense pain, all vanity went out the window.
I've found bathing your eye in milk seems to work work well, although my eyes can seem to take the odd ark flash these days without hurting, can't say the same for my face skin Lol.
It works due to the whole eye surface gets micro-blistered. Potato Starch and Corn starch is really slick and soothing. I get Eye-Diamonds (undissolved salt deposits) that try to make it through the tear ducts that are located under the upper eyelids and get stuck at the ducts ends. They point through like a diamond stylus and wreak havoc on the surface of either eye that it happens to. To not suffer from "Sandman Level: INFINITY+100", I have to take a strong Lorazapam and sleep for a few hours till it dissolves on it's on. Luckily it usually only happens every couple of months.
My local hardware store has been recently dumping a bunch of UVC products off in the bargain bin for very cheap. Lots of both Mercury Vapor, and LED style products to choose from. Ripe for gutting them to get components fairly inexpensively. I got a whole pile of parts for less than 10 bucks. 👌
I like longer videos with the narration. It’s really nice watching the tear down and then trying to guess how the schematic will end up looking. I’ve learned a lot from this channel. It’s helped some Circuit idioms click in my head. Right now I have my very own ghost dispelling, Christmas light, Joule Thief mini light running on the shelf. Built that yesterday after inspiration from you.
This "tester of death" is probably safer than what they used to do at the Co-Op when I was a nipper. Light bulbs were tested at the till using a presumably always-live batten lampholder screwed to one of the panels in the till area. At least this has a switch!
Back in the 1970s, every serious philatelist in Britain had a UV light as part of their Postage Stamp Collector's kit, in order to tell the difference between the 1960s Commemorative issues with and without the phosphor bands or blocks. These bands were used by early POST OFFICE automatic sorting machines. Sometimes, the only way to know the difference between identical stamps with or without phosphor was to look at them in a dark room with this UV light. Without phosphor had say, a value of say 5p, with phosphor was £20. I used to use my father's UV lamp as a child and remember the headache it used to give me if you used it for more than a few seconds. I seem to remember there was a switch for UV Longwave and Shortwave. They were for different phosphor band types. The UK used one type and other countries such as the US used the other?
The reversed electrolytic capacitor - probably isn't. Any positive current will flow through the transistor, so the capacitor won't get any of that charge. But, when a current is induced in that coil, you can think of it like putting a battery there, with the positive side going into the transistor, and the other side will be negative, so can charge that capacitor's negative side. The 3.3nf is important, as the current will flow through and charge this capacitor via the heating elements. Once it is full, the current will stop, causing voltage of the inductor to spike until it can discharge via the gas in the tube until the 22nf capacitor is full. This tells you how much will go through the heating element verses how much goes through the gas (I think... that sound about right?)
I put in CFL bulbs around the house way back when CFL was in and LED had not taken off yet. I am quite pleased in that I have not had to change out very many of them. I'm not going to replace them while they are still working. I'll just dispose of them properly as the time comes.
Hi Clive! I appreciate these longer videos because they are hugely enjoyable (and take my mind off my forthcoming shift). I also have 'the vice of knowledge'. It makes an excellent nutcracker! 👍
Your voice is so soothing. You are my medicine for insomnia. I always watch your videos twice. In the evening to fall asleep because of your voice and in the morning because of the content! Keep it up!
Capacitor is backwards by accident, but with only 0.6V reverse bias it will survive as long as if run at rated voltage the right way, as the cathode foil, normally just there to provide the connection to the electrolyte, does have a 10V or so oxide layer that is formed naturally on it, so it does act like a capacitor. The 2n2 capacitor is part of the start up, it provides a pulse of current to turn the bottom transformer when mains is applied, and also does provide some filtering of HF noise to the central switch, limiting the turn on and turn off times of both transistors. Otherwise that 300k is not enough, with moderately hot and leaky transistors, to actually provide the slight bias needed to turn on the transistor, which will, by the positive feedback through the base drive coil, turn on hard til the capacitor is nearing full charge, reducing current, and then it will be turned off hard, while the other is being turned on hard. you need that turn on transient, especially if you are turning a hot lamp back on, and the transistors and capacitors are now hot and leaky enough.
I have this tiny vice I have had since I was a kid back in the 80s and I have been a mechanic since the early 90s. In my shop I have a huge vice we use for most things and I have the little one for small things. One day this guy from Australia who works for me took a sharpie and drew palm trees and wrote Miami Vice on it. I thought that was hilarious so I clear coated it so it stays. 😂
Never heard the potato cure for arc eye, but have experienced arc eye and it is very unpleasant! I use an eye bath of milk which brings immediate relief. Another erudite and well explained video, thanks Clive, you are the electrical industries gold standard! Phil
I was a welder for many years, never heard of potato juice but some of my friends tried tea-bags with various degrees of success. I used Optrex with some success, best solution is not to look at the arc
I have a pair of those identical UVC tubes sitting right beside me! Yes, they're off. ;) Mine came with caps for the 2nd end plug, as well as an inline connector. You use that so you can easily daisy chain a bunch of tubes. I've got mine hooked to a Kasa remote plug - I put it in the room to be UV'd, then just call out "Alexa, turn on the lamp of death". After about 20 minutes, the whole room smells like a fresh lightning storm just rolled through it.
I also have one of those tubes and mine also came with the bits you mention. I put mine in my bedroom and left it on for an hour while I watched an episode of The Professionals. When I went up to unplug it the room was awash with ozone, so much so that I couldn't breath and had to vent the room. This is the most powerful UV/ozone generator I own (and i have several) ! !
I had a mini blender which must have had a current limit capacitor. I lost count of the number of times I got a belt (and I mean really painful) from it after unplugging it, even if it had not been running for several minutes (so not a run capacitor). Clearly no or insufficient discharge resistor. Courtesy of Morrisons.
I've got a coffee grinder which does that, got into the habit of touching the plug to some earthed metalwork after unplugging. Also had a couple of sanders and a paper shredder which did it.
I've noticed the integrated bridge rectifier seems to be what pops over time. The first lamp's chip seems a tiny bit larger than the usual ones I take apart, so maybe there's a higher wattage rating manufacturers don't use?
Cool video! I can vouch for the eye discomfort from welding arc radiation; I vividly remember the agony when I was about eleven years old after a day with my dad's Tig welder; where I was learning everything the hard way. My dad was quite lazy and never taught me much but also the lack of adult supervision meant that I could play with whatever the heck I wanted. My school teachers didn't like me much for my inquisitiveness; especially when I tricked them several times into receiving electric shocks from little capacitors hidden in toys I put there for only one reason. Like you Clive, I do have one of the UVC 'flesh burning death lamps' and I think it's fun.
Hi Big Clive, they have not yet reached UVC with solid state LEDs. I have some 385nm and 405nm both UVA. UVC is 254nm, very bad stuff. Thank you for all of your great work. I have learned bunches from you.
UVC starts at around 280nm, and you can definitely get leds at those wavelengths. They used to be really expensive (paid about $20 per milliwatt in 2016) but prices have dropped recently. Even the 265nm diodes are getting pretty cheap.
254nm LEDs do in fact exist. They are still quite expensive and somewhat scarce. "SunTech LED" is one of several manufacturers that have English language web sites.
UVC LEDs are built into a tiny metal container with ceramic insulators a quartz lid. Can't use plastic of any kind, because the UVC would destroy it. They are expensive to build. Much cheaper to use a mercury vapor tube of some kind.
Clive, I've been looking everywhere for "blank" light bulbs, just the screw fitting and the glass. I've called a number of suppliers and specialists, and none of them have any access to them. Have you ever looked into this?
@@bigclivedotcom 3-way by chance? I'd like to convert an Edison style Y adapter that holds two bulbs in one socket to fit a 3-way socket. So it turns on one, then the other, then both. Then I can use normal LEDs in my 3-way lamps. The 3-way LEDs cost MUCH more than buying two bulbs with similar wattage and physical size.
The actual UV tube does have a delicious color. When I was doing welding a whole bunch of years ago I always wore a leather jacket, long pants and a mask with a proper viewing glass to block all of the UV.
Oh yeah, I should also mention that one time I was doing some fit up of parts with my back turned when my mentor was MIG welding up some products. I wasn't doing any welding so I didn't think about safety but the backs of my arms and the back of my neck got burns from the UV.
Sony used a similar but far more complicated circuit, based on the same idea but clocked at line speed in a few television sets, for many years. The purpose of the 2n2 capacitor is as a tuning capacitor and snubber. If you draw the 2n2 ton the right hand side of the transistor (between the Emitter [after the 5R1] and collector) it is more obvious. Nice video.
From my limited experience with CFLs, they seem to go bang when one of the filaments fail and the electronic ballast ends up oscillating under "open lamp" conditions. Then the lamp either HV-starts from back-EMF from the inductor and whatever little current manages to go through or the oscillator self-destructs either from unstable oscillation at excessively high frequency or excessive back-EMF from the inductor. The 2.2nF capacitor may be a crude way to protect the transistors from inductor back-EMF under open-lamp conditions.
I have several of those striplights, also with resonant start like yours. I'd wondered how to get them apart without destroying them .. maybe an end connector can be disassembled non-destructively to get the guts out and fix the things? Plenty of early failures with these but the ones which survive tend to last for years. So do the tubes. Lyvia Linklights in my case, the T4 versions.
I don't know if he mentioned it in the video yet but your screen that you're watching this on cannot reproduce UVC light so it's perfectly safe to watch the bulb on a video screen you just don't want to look into them in person, it would be the equivalent of looking at a welding arc
How do you know what type of screen I'm watching this on? But on a serious note, I wonder if there are any displays which work with UVC. I know LCDs can deal with near UV as used in resin printers.
Long videos are fine. If we need to split our viewing into segments, we can pause it and start it up again later. Same with the build videos where you leave in long segments of soldering LEDs or something. We can simply skip ahead if we don't want to watch it all.
Mmhhmm... that amazing color. I love it. I have an electric toothbrush from Philips and the older model I used to own came with a sterilizer for the brush heads. I still use it and it uses one of the real small UV-C lamps and I always loved the glow when it was on. You can see it through some sort of "mesh filter" as a window - kinda like the Microwave-oven doors.
The 2n2 capacitor is effectively across the output of the half bridge. It's being charged to 300V and discharged to 0V every cycle. The only thing I can think of for its purpose is to take the edge out of the switching waveform and reduce EMI, but it's a very brutal way of doing it. Hard on the capacitor and hard on the transistors.
I have a real UVC 43cm tube (G15T8)- bought from an electronics shop over 30 years ago to erase E-Proms used in a uPC project I was developing then. It lives in a timber box to prevent any stray radiation when in use - the safety aspect was impressed on me from day one ;) The lamp holder is like the standard 20W flouro type with a 'flicker' type starter and an inbuilt ballast IE no electronic control at all.
I have one of those too. I haven't chucked it yet, nor have I found a good use for it. I found that regular blue LEDs put out a lot of UV, probably the longer wavelength.
I do not see a need for splitting this. Of course you could split it into 20 parts, and make shorts-tube happy, but beside that I like videos providing content and are a bit longer much more than I like short videos missing half of the explanation.
Juice from a potato definitely works for arc burn. It also helps with other eye irritants. I got a spark from a cutoff saw. We thought it was burn, so we treated it with potato juice. It releaved the discomfort for a few days til I could get to an eye doctor. The joys of working on the road.
I suppose the starchy water potentially could serve as a barrier and reduce inflammation. Probably more placebo than anything, though. Best to just avoid it happening at all.
"Oooh that is tight, that is a very tight fit." and the "vice of knowledge" are just a peppering of the musical commentary which I love about your videos.
"Let's see if I can stab myself in the process". As somebody whose hands are a garden of scars thanks to tiny bits, I really appreciated that nonchalant delivery.
Back in the days when grabbing moments meant taking part-finished work to the toilet, I had only the aluminium face of the project box to drill for the pattern of holes through the paper template I had stuck on. The closed box clamped between the bare knees and with the basic cordless drill I sat on until both tasks were completed. I set the work aside and completed the paperwork, but it was only when I stood and pulled up the kecks that I found where the swarf had collected.
A while back I got a couple small UV flashlights from a bin at a big box hardware chain; they carry the logo of a formerly reputable, formerly American tool brand. They are, to all appearances, identical. One of them is your run-of-the-mill UVA purple, the other however really looks like UVC blue and makes things fluoresce real good so I don't play around with it. Or would there be a likelihood of it being UVB, which you don't hear much about?
If it has standard plastic LEDs then it's possibly that the casing is fluorescing and adding the blue look. A real UVC LED flashlight would be very expensive.
If you measure the running voltage on that "reverse connected" capacitor, you will find it is correct. When running, the transformer winding pulls the base on the BJT positive and the other end of the winding wants to go negative. The voltage will be small but the capacitor's voltage will end up negative once the thing is running.
I couldn't help but comment on the operation of the UVC fluorescent driver. What seem to be missing is the correct operation of the circuit it is a half Bridge Inverter. The inductor (typically around 4-2mH and the two capacitor 22nf and the 3n3f form a series resonant circuit. That oscillates some where around 100-60KHz. Because the tube is an open circuit at startup this heats up the filaments (current at startup is 3-4 times higher than the run current) and this also causes a high voltage around the 3n3f capacitor > 600 volts, so when the filaments are hot enough the high voltage strikes the tube causing it to be largely ohmic (i.e. a resistor). This effectively removes the 3n3f capacitor from the circuit causing the frequency to drop to around 20KHz or so. The current that now flows through the tube keeps the filament hot enough. The whole process and design of CFL lamps is explained very nicely in Philips Application Note AN99065. the side of the 22nf capacitor connect to the 340volt rail is effectively at AC ground so it could be connected the the 0 volt rail. The design in AN99065 uses a two capacitors one connected to the 340 volt rails and the other connected to the 0 volt rail. Also if you google CFL schematics and take a look at the web site by pavouk you will see lots of circuits and an explanation of the working of these inverter circuits. Its a bit hard to follow as the writer is not an native English speaker.
18:20 "...and yet they keep working..." I used to maintain the communal lighting of our appartment building and in it CFLs were used. On at dusk, off at dawn. I guesstimated 5,500 hours in operation every year. Most cfls would do 2 to 3 years that way, so way more than their advertised 6,000 or 8,000 hours (one of which managed 12 years!!! or 66,000 hours!!!). Then came the retrofit LED bulbs that would promise 15,000 or even 25,000 hours but all with a more than 470 lm rating would die very quickly, some not even reaching the lifespan of an incandescent bulb.They were baked way more inside than the CFLs. As a result I replaced them with integrated LED fixtures, some consumer ones promising only 15,000 hours and some semi-commercial ones promising 35,000 hours. They were installed in 2016 and are ALL still working perfectly today, almost 7 years later.
I noticed how you held the lamp in vice, at onetime I was doing a small production run and I needed to hold a quantity of pieces of 2 inch diameter aluminium stationary while drilling holes in the face, I put the vice in a 4 jaw chuck and machined a round face on the jaws. If you do not have access to a metal lathe possibly you could get a piece of wood and drill a 2 inch diameter hole with a hole saw and saw it through the centre and make two soft jaws, . Something to think about, David
I know they will probably be almost impossible to get hold of and cost prohibitive, but a future video of the new 222nm far UVC lamps that are human safe would be amazing.
The two windings on the toroid probably run the end heaters ease the arc strike. to have some fun put a bench supply across the heater and note the heater resistance is smaller than the arc across the resistance of the filament
Used to be a welder in a past life - had arc-eye a couple of times - the first (and worst) time was from a brief factory tour when I was an office boy. Had never heard of it, didn't expect it and it came on whilst I was driving home hours later in the day - not something to be recommended. Cold, used tea-bags resting on closed eyes was the recommended treatment in the day (proper teabags, I hasten to add!), no idea if it actually helped or not...
Not understanding why the capacitor is apparently backwards is obviously a call for "I wonder what would happen if..." I flipped the capacitor right-way-round. I mean, how bad could it be?
On the first PCB the electrolitic is labelled 4.7uF 250v, so I guess the 330 is the resistor value for a 120 volt version along with a bigger, lower voltage, capacitor.
I purchased a Samsung wireless charger with a uv sterilisation unit in when closed and on, it does illuminate and the light works on a timer, im unsure if it works but it was used on eBay for £1 so could not leave to rest on eBay shelves.
The spectrum of a UV Mercury lamp is fundamentally different from LEDs. Mercury has a band spectrum meaning that besides its continuum spectrum, it has several peaks because of electron transitions. Some are in the visible region. UVC lamps must have argon too. As our brain synthesizes the sensation of color from the 3 color receptors the sensation can be the same for different spectra. But LEDs emmit on a very narrow band. There are two main UV-C LEDs the ones with Gallium-Nitrogen and the ones with Aluminuium-Gallium-Nitrogen. They usually emit at 260 or 280nm or both (this is considered more efficient in disinfection). My point is that the color means very little and the LEDs tend to have a color more akin to violet if they invade the visible spectrum. As UV-C and UV-A LEDS have a similar construction the voltage drop on them is also not an indicator. The better way is to use UV-C dosimeter cards they are created specifically to test if the device emits UV-C and tell if they are safe or dangerous and determine the exposition time to kill bacteria. They change color depending on the dosage of UV-C received.
This potato ritual is said to ease suffering; you can have eye drops ready, or you can use a fresh cool potato, at least as a placebo - should calm you, if not your eyes, down. ;D I myself didn't notice much difference - after a while you get better, if only not exposed to welding sparks / harmful UV light for too long.
Thank you as always (or often) Clive, for adding to, or clarifying abstract bits of, one of my current research rabbit holes! After learning about the medical studies on 222 nm UV being optimal for breaking microorganisms dna without penetrating human skin, I looked into all the UV bulbs available for whatever purposes and, crikey, I should have known..:::😂😂😅 ¡Salud! to human engineering and the joy of our desiring to tinker with local conditions...::💎⚡💚💚💚
From Wikipedia: UV (UV-C) considered "germicidal UV". Wavelengths between about 200 nm and 300 nm are strongly absorbed by nucleic acids. The absorbed energy can result in defects including pyrimidine dimers. These dimers can prevent replication or can prevent the expression of necessary proteins, resulting in the death or inactivation of the organism. Mercury-based lamps operating at low vapor pressure emit UV light at the 253.7 nm line.[15] Ultraviolet light-emitting diode (UV-C LED) lamps emit UV light at selectable wavelengths between 255 and 280 nm.[16] Pulsed-xenon lamps emit UV light across the entire UV spectrum with a peak emission near 230 nm
A while back I tried the old desktop computer power supply to desktop power supply thing. It was old, so I powered it up to make sure it worked before starting. Now I had to discharge the capacitors. It was the first time I had ever done anything like that. There was a very loud bang that scared the crap out of me. My wife was in the other room and even she was startled. I decided to let it sit for 48 hours instead of doing that again.
Hi Clive, Do you know if UVC LEDs can be designed to generate ozone or is it only the tubes (With untreated quartz glass of course) that can ? Also I'm still a lil' bit worried about the possible end of all non-LED lighting products (From halogen bulbs and fluorescent tubes for illumination to blacklight and UVC tubes).
I don't think there are commercial UVC LEDs in the 184nm region yet. It's probably cheaper and easier to do it with a corona discharge system for low output applications.
I got a UVC lamp of banggood to sterile the house to 'protect' my mum, and it following the instruction for the time for the size of room said 20 minutes, after 5 minutes the ozone smell was unbelievable and took 6 hours with all the doors and windows open for it to go 😬
Aye. I stumbled on a 55W tube unit at a thrift store for $5 with an RF remote so it can be turned on and off out of line-of-sight. It generates a huge amount of ozone. We had a mold problem in the basement and it was very helpful to keep it under control until we could get the damaged wood and drywall out.
Is really helpful though. The ozone'll kill mould, bed bugs, fleas etc etc. If you really don't like it, a 253nm UVC light is better at killing directly, and breaks down ozone faster than it creates ozone (as opposed to the 185nm, which creates ozone faster than it breaks ozone). Obviously, using it for direct sterilisation does mean it only kills on direct line-of-sight, or reflections from aluminium. Most other materials won't reflect much of the UVC. The ozone can be good to clean the bathroom, stop mould forming from humidity after a shower/bath. A timer switch could turn it on for 10 mins at night, have it fresh for the morning.
I’ve had flash many times. Cold wet teabags do the job and lots of whiskey (the whiskey is to drink, not for your eyes). Great video Clive and I’m still waiting for my Aliexpress delivery 😂
"The Vice of Knowledge." Classic. Reminds me of my elementary school days, when the school principal explained to the student body that if we misbehaved he "would not hesitate to apply the Board of Education to the Seat of Learning." Of course, today, he would go to jail for simply saying that.
I bought these exact same lamps when the pandemic hit, you don't have a mini cob bulb, it has the most lovely ice blue I've ever seen, no uvc and super exposed voltage but it's pretty
2.2nF cap is probably like a snubber. When the transistor turns off, it filters voltege spike over the other transistor (there is an inductor after all and it makes a spike because those switch off most probably before zero crossing). You could draw it across one transistor and it would seem more clear. Why only one, why not one for each transistor? Because they are cheap. It is cheaper than two separate caps and there probably is enough voltage margin to get by with just one. The effect of cap is also to help keeping the voltage zero during transistor turn off period. If current was flowing through the partially conducting transistor, it would result in switching losses when there is current flowing through a partially conducting transistor. Things like that are quite common for resonant switching power supplies. (Or quasi-resonant like this one surely must be)
I have had first hand experience of a bad flash from welding. Basically you get a wet flannel over the eyes, lay down in a dark secluded room and scream until the next morning.
What was the phantom resistor about shown at the right hand side of the bottom PCB - after the bridge and before the caps? Was this an "anticipated component" that was "ooooh, it's not there, ok!" :) ?
I got a true UVC lamp (for sterilising water in fish tank filters) a couple of years back on amazon. I was dubious that it was real until I saw a one star review from someone who complained it killed all their fish... I knew I had to have it. When I turned it on and smelt the fresh ozone I knew it was the real deal. I put it into a box lined with reflective tape and an interlock (must be closed to operate) and used it for sterilising things at the start of the pandemic, when paranoia wasn't paranoia.
dont take this the wrong way clive ,but i like the longer videos !! i put them on my second monitor when i work to keep me company , short videos dont do it since i dont want to fiddle around and change videos every 5 min ,
If you get arc flash, or snow blindness. You can uses sustain eye drops. It works for non operating mybomian glands which feels worse. Take care of your eyes.
I picked up a somewhat dubious phone sanitizer (with aromatherapy oil diffuser well heated by a power resistor!) for $5 at wally world after the hair on fire coof panic started wearing off. Really only bought it to see if it was a scam but was pleasantly surprised to find 3 actual UVC leds; it was probably still a scam since I don't see how 3 LEDs pointing at the edge of a phone could sterilize it, but technically it was emitting it. Given just the chips easily go for $2.50 a piece direct from China I should have gone back and bought 4 more before the mostly untouched pallet full was sent to the landfill or sold to a thrift store.
How much roughly do regular eye glasses protect your eyes from uvc? Is it safe enough to leave the light on while in the room or is it still necessary to leave asap? Can too much ozone be harmful if I leave the uvc light on overnight to sanitize/sterilize my kitchen for example? I have little to no airflow from my kitchen to my bed room due to how my apartment is ventilated.
@@Okurka. Are you really that ignorant that you think I would not first clean "normally" before using uvc radiation and ozone? Do not answer just to keep your keyboard buissy, think first.
@@Okurka. You made a assumption about me that you have neither the knowledge or basis to make as you do not know me at all. You insulted me and my character with no cause or right, so FU*K YOU to.
I've got 30w uvc for pond helps get rid of alge clear tube sits inside exspensive quartz tube in which pond water flows round,tubes sat inside larger plastic cylinder.which also gives good protection to eyes, Had to replace quartz tube once3' cost around £30.
Videos of this length are perfect Clive, no need to split it
lol i just watched the whole video and didn't realise it was 20 minutes long!
Did you mean videos of this wave length?
I concur, long format is great for listening while at work
Ten minutes on 2x... not long at all!
Yep. I actually like the longer videos. 👌
I love the longer videos but am happy with any of your production :)
Being someone who suffers from chronic cornea damage, I do not recommend potato juice. I am also not going to give medical advice but there are over the counter eye drops that will address swelling and pain without the risk of an eye infection. Great video either way, Clive. Thanks as always.
As someone who has suffered from weld flash a couple of times, the potato works. Just cut it in half and put each half on your eyes like you're relaxing at the spa. The first time I got hit, it was bad, and i tried the eye drops. They did nothing. I finally broke down and listened to the "old-timers." It was near instant relief. I felt silly doing it, but after spending a night, blind and in intense pain, all vanity went out the window.
I've found bathing your eye in milk seems to work work well, although my eyes can seem to take the odd ark flash these days without hurting, can't say the same for my face skin Lol.
I prefer tobramycin/dexamethasone ointment for sleeping.
It works due to the whole eye surface gets micro-blistered. Potato Starch and Corn starch is really slick and soothing. I get Eye-Diamonds (undissolved salt deposits) that try to make it through the tear ducts that are located under the upper eyelids and get stuck at the ducts ends. They point through like a diamond stylus and wreak havoc on the surface of either eye that it happens to. To not suffer from "Sandman Level: INFINITY+100", I have to take a strong Lorazapam and sleep for a few hours till it dissolves on it's on. Luckily it usually only happens every couple of months.
My local hardware store has been recently dumping a bunch of UVC products off in the bargain bin for very cheap. Lots of both Mercury Vapor, and LED style products to choose from.
Ripe for gutting them to get components fairly inexpensively. I got a whole pile of parts for less than 10 bucks. 👌
I like longer videos with the narration. It’s really nice watching the tear down and then trying to guess how the schematic will end up looking. I’ve learned a lot from this channel. It’s helped some Circuit idioms click in my head. Right now I have my very own ghost dispelling, Christmas light, Joule Thief mini light running on the shelf. Built that yesterday after inspiration from you.
I like that you are using the "tester of death" for this review.
I like these units a lot for their amusing lack of safety. I'll have to remember to include warnings every time I use one.
@@bigclivedotcom you wouldn't want to lose any SUBSCRIBErs.
This "tester of death" is probably safer than what they used to do at the Co-Op when I was a nipper. Light bulbs were tested at the till using a presumably always-live batten lampholder screwed to one of the panels in the till area. At least this has a switch!
@@BG101UK oh yes, I'd forgotten they used to test bulbs before you took them home as a kid.
@@Okurka. I'd leave the shock in too. Assuming I didn't die.
Back in the 1970s, every serious philatelist in Britain had a UV light as part of their Postage Stamp Collector's kit, in order to tell the difference between the 1960s Commemorative issues with and without the phosphor bands or blocks. These bands were used by early POST OFFICE automatic sorting machines. Sometimes, the only way to know the difference between identical stamps with or without phosphor was to look at them in a dark room with this UV light. Without phosphor had say, a value of say 5p, with phosphor was £20. I used to use my father's UV lamp as a child and remember the headache it used to give me if you used it for more than a few seconds.
I seem to remember there was a switch for UV Longwave and Shortwave. They were for different phosphor band types. The UK used one type and other countries such as the US used the other?
The reversed electrolytic capacitor - probably isn't. Any positive current will flow through the transistor, so the capacitor won't get any of that charge. But, when a current is induced in that coil, you can think of it like putting a battery there, with the positive side going into the transistor, and the other side will be negative, so can charge that capacitor's negative side.
The 3.3nf is important, as the current will flow through and charge this capacitor via the heating elements. Once it is full, the current will stop, causing voltage of the inductor to spike until it can discharge via the gas in the tube until the 22nf capacitor is full. This tells you how much will go through the heating element verses how much goes through the gas (I think... that sound about right?)
It probably wouldn't be too difficult for LED manufacturers to make a nice turquoise LED phosphor to "simulate" UVC lamps more accurately.
They did. A lot of the fake lamps being sold during the pandemic were very bright ice-blue ones. Search my channel for fake UVC to find them.
They sure did... Trying to fool the people with 405nm LEDs seemed to be a popular method also
Should be criminal to sell things claiming to have medical or disinfecting properties when they don't.
@@LeifNelandDk Newsflash, fakes are not real products, Leif news reporting.....
@@LeifNelandDk : It actually is criminal. It's called fraud and conspiracy to commit fraud. It could even result in charges of medical assault.
I put in CFL bulbs around the house way back when CFL was in and LED had not taken off yet. I am quite pleased in that I have not had to change out very many of them. I'm not going to replace them while they are still working. I'll just dispose of them properly as the time comes.
still got some cfl that keep on truckin. Only question I couldn't find an answer for is why their lightoutput decreases so much over time
The technical name for UV eye irritation is called Photokeratitis and it's very uncomfortable.
@@Okurka. Congrats on being useless.
@@Okurka. I know this is surprising to you, but some people actually know things.
Just over a minute in and the vice of knowledge makes its appearance! :D
Hi Clive! I appreciate these longer videos because they are hugely enjoyable (and take my mind off my forthcoming shift). I also have 'the vice of knowledge'. It makes an excellent nutcracker! 👍
Your voice is so soothing.
You are my medicine for insomnia.
I always watch your videos twice.
In the evening to fall asleep because of your voice and in the morning because of the content!
Keep it up!
HI Clive. I like long videos--much more enjoyable for me. Thanks.
I always enjoy your video's and the description of the associated circuitry. Much appreciated.
I have found that a tea bag soaked in luke warm water and applied wet to the eyes is very soothing for arc flash.
Capacitor is backwards by accident, but with only 0.6V reverse bias it will survive as long as if run at rated voltage the right way, as the cathode foil, normally just there to provide the connection to the electrolyte, does have a 10V or so oxide layer that is formed naturally on it, so it does act like a capacitor.
The 2n2 capacitor is part of the start up, it provides a pulse of current to turn the bottom transformer when mains is applied, and also does provide some filtering of HF noise to the central switch, limiting the turn on and turn off times of both transistors. Otherwise that 300k is not enough, with moderately hot and leaky transistors, to actually provide the slight bias needed to turn on the transistor, which will, by the positive feedback through the base drive coil, turn on hard til the capacitor is nearing full charge, reducing current, and then it will be turned off hard, while the other is being turned on hard. you need that turn on transient, especially if you are turning a hot lamp back on, and the transistors and capacitors are now hot and leaky enough.
I was going to comment on the purpose of the 2n2 capacitor but you beat me by 1 hour
I have this tiny vice I have had since I was a kid back in the 80s and I have been a mechanic since the early 90s. In my shop I have a huge vice we use for most things and I have the little one for small things. One day this guy from Australia who works for me took a sharpie and drew palm trees and wrote Miami Vice on it. I thought that was hilarious so I clear coated it so it stays. 😂
Never heard the potato cure for arc eye, but have experienced arc eye and it is very unpleasant! I use an eye bath of milk which brings immediate relief. Another erudite and well explained video, thanks Clive, you are the electrical industries gold standard!
Phil
I suppose the starch suspended in the potato juice acts like talc. Not sure how beneficial it is for the eyes in the long run, though.
I was a welder for many years, never heard of potato juice but some of my friends tried tea-bags with various degrees of success. I used Optrex with some success, best solution is not to look at the arc
Damp used teabags.
Thanks. A very interesting and informative video. Your photos and schematics are a valuable asset to the final production.
I have a pair of those identical UVC tubes sitting right beside me! Yes, they're off. ;)
Mine came with caps for the 2nd end plug, as well as an inline connector. You use that so you can easily daisy chain a bunch of tubes. I've got mine hooked to a Kasa remote plug - I put it in the room to be UV'd, then just call out "Alexa, turn on the lamp of death". After about 20 minutes, the whole room smells like a fresh lightning storm just rolled through it.
Better air it out afterwards. Ozone can really rot rubber.
I also have one of those tubes and mine also came with the bits you mention. I put mine in my bedroom and left it on for an hour while I watched an episode of The Professionals. When I went up to unplug it the room was awash with ozone, so much so that I couldn't breath and had to vent the room. This is the most powerful UV/ozone generator I own (and i have several) ! !
I had a mini blender which must have had a current limit capacitor. I lost count of the number of times I got a belt (and I mean really painful) from it after unplugging it, even if it had not been running for several minutes (so not a run capacitor). Clearly no or insufficient discharge resistor. Courtesy of Morrisons.
That sounds like a suppression capacitor on the incoming supply.
I've got a coffee grinder which does that, got into the habit of touching the plug to some earthed metalwork after unplugging. Also had a couple of sanders and a paper shredder which did it.
I've noticed the integrated bridge rectifier seems to be what pops over time. The first lamp's chip seems a tiny bit larger than the usual ones I take apart, so maybe there's a higher wattage rating manufacturers don't use?
Cool video!
I can vouch for the eye discomfort from welding arc radiation; I vividly remember the agony when I was about eleven years old after a day with my dad's Tig welder; where I was learning everything the hard way. My dad was quite lazy and never taught me much but also the lack of adult supervision meant that I could play with whatever the heck I wanted. My school teachers didn't like me much for my inquisitiveness; especially when I tricked them several times into receiving electric shocks from little capacitors hidden in toys I put there for only one reason.
Like you Clive, I do have one of the UVC 'flesh burning death lamps' and I think it's fun.
Hi Big Clive, they have not yet reached UVC with solid state LEDs. I have some 385nm and 405nm both UVA. UVC is 254nm, very bad stuff. Thank you for all of your great work. I have learned bunches from you.
UVC starts at around 280nm, and you can definitely get leds at those wavelengths. They used to be really expensive (paid about $20 per milliwatt in 2016) but prices have dropped recently. Even the 265nm diodes are getting pretty cheap.
254nm LEDs do in fact exist. They are still quite expensive and somewhat scarce. "SunTech LED" is one of several manufacturers that have English language web sites.
UVC LEDs are built into a tiny metal container with ceramic insulators a quartz lid. Can't use plastic of any kind, because the UVC would destroy it. They are expensive to build. Much cheaper to use a mercury vapor tube of some kind.
Back in the day, the power company mailed out free compact fluorescent bulbs...they had a warning that a small explosion was a normal failure mode...
Clive, I've been looking everywhere for "blank" light bulbs, just the screw fitting and the glass. I've called a number of suppliers and specialists, and none of them have any access to them. Have you ever looked into this?
Look online for an E27 bulb or lamp kit. They do sell the bare housings.
@@bigclivedotcom 3-way by chance? I'd like to convert an Edison style Y adapter that holds two bulbs in one socket to fit a 3-way socket. So it turns on one, then the other, then both. Then I can use normal LEDs in my 3-way lamps. The 3-way LEDs cost MUCH more than buying two bulbs with similar wattage and physical size.
@@strehlow Take a dead 3 way bulb and do the crunchy work to liberate the base intact, then you can modify the Y adapter to fit it in there.
@@SeanBZA Yeah, at some point I will. But the two I have in use are both LED so it might be a while.
The actual UV tube does have a delicious color. When I was doing welding a whole bunch of years ago I always wore a leather jacket, long pants and a mask with a proper viewing glass to block all of the UV.
Oh yeah, I should also mention that one time I was doing some fit up of parts with my back turned when my mentor was MIG welding up some products. I wasn't doing any welding so I didn't think about safety but the backs of my arms and the back of my neck got burns from the UV.
In the past time, I used tubular germicidal lamp for erasing electronically programmable read only memory (EPROM) content.
Sony used a similar but far more complicated circuit, based on the same idea but clocked at line speed in a few television sets, for many years. The purpose of the 2n2 capacitor is as a tuning capacitor and snubber. If you draw the 2n2 ton the right hand side of the transistor (between the Emitter [after the 5R1] and collector) it is more obvious. Nice video.
From my limited experience with CFLs, they seem to go bang when one of the filaments fail and the electronic ballast ends up oscillating under "open lamp" conditions. Then the lamp either HV-starts from back-EMF from the inductor and whatever little current manages to go through or the oscillator self-destructs either from unstable oscillation at excessively high frequency or excessive back-EMF from the inductor. The 2.2nF capacitor may be a crude way to protect the transistors from inductor back-EMF under open-lamp conditions.
I have several of those striplights, also with resonant start like yours. I'd wondered how to get them apart without destroying them .. maybe an end connector can be disassembled non-destructively to get the guts out and fix the things? Plenty of early failures with these but the ones which survive tend to last for years. So do the tubes. Lyvia Linklights in my case, the T4 versions.
I love the flurocent lamps and you!!!!
I don't know if he mentioned it in the video yet but your screen that you're watching this on cannot reproduce UVC light so it's perfectly safe to watch the bulb on a video screen you just don't want to look into them in person, it would be the equivalent of looking at a welding arc
And I guess the UV may not be recorded as UV either.
How do you know what type of screen I'm watching this on? But on a serious note, I wonder if there are any displays which work with UVC. I know LCDs can deal with near UV as used in resin printers.
You have to have a super wide gamut monitor.
Long videos are fine. If we need to split our viewing into segments, we can pause it and start it up again later. Same with the build videos where you leave in long segments of soldering LEDs or something. We can simply skip ahead if we don't want to watch it all.
Mmhhmm... that amazing color. I love it.
I have an electric toothbrush from Philips and the older model I used to own came with a sterilizer for the brush heads. I still use it and it uses one of the real small UV-C lamps and I always loved the glow when it was on. You can see it through some sort of "mesh filter" as a window - kinda like the Microwave-oven doors.
The 2n2 capacitor is effectively across the output of the half bridge. It's being charged to 300V and discharged to 0V every cycle. The only thing I can think of for its purpose is to take the edge out of the switching waveform and reduce EMI, but it's a very brutal way of doing it. Hard on the capacitor and hard on the transistors.
I have a real UVC 43cm tube (G15T8)- bought from an electronics shop over 30 years ago to erase E-Proms used in a uPC project I was developing then. It lives in a timber box to prevent any stray radiation when in use - the safety aspect was impressed on me from day one ;)
The lamp holder is like the standard 20W flouro type with a 'flicker' type starter and an inbuilt ballast IE no electronic control at all.
I have one of those too. I haven't chucked it yet, nor have I found a good use for it. I found that regular blue LEDs put out a lot of UV, probably the longer wavelength.
@@jamesvandamme7786 Not so much that they produce UV as the blue photons are energetic enough to have similar effects, especially fluorescence.
I do not see a need for splitting this. Of course you could split it into 20 parts, and make shorts-tube happy, but beside that I like videos providing content and are a bit longer much more than I like short videos missing half of the explanation.
Maybe I'll make some shorts out of it.
Juice from a potato definitely works for arc burn. It also helps with other eye irritants. I got a spark from a cutoff saw. We thought it was burn, so we treated it with potato juice. It releaved the discomfort for a few days til I could get to an eye doctor. The joys of working on the road.
I suppose the starchy water potentially could serve as a barrier and reduce inflammation. Probably more placebo than anything, though. Best to just avoid it happening at all.
"Oooh that is tight, that is a very tight fit." and the "vice of knowledge" are just a peppering of the musical commentary which I love about your videos.
The Vice of Knowledge!
It's become a ritual of nonsensical fake sterilisation.
@@bigclivedotcom yeah, a nice commentary on outdated and no longer adequate pandemic practices.
@@bigclivedotcom what do you mean fake? I get arc eye every time!
@@bigclivedotcom Will it happen this week's stream, and when?
@@TheChipmunk2008🙃
"Let's see if I can stab myself in the process". As somebody whose hands are a garden of scars thanks to tiny bits, I really appreciated that nonchalant delivery.
Back in the days when grabbing moments meant taking part-finished work to the toilet, I had only the aluminium face of the project box to drill for the pattern of holes through the paper template I had stuck on. The closed box clamped between the bare knees and with the basic cordless drill I sat on until both tasks were completed. I set the work aside and completed the paperwork, but it was only when I stood and pulled up the kecks that I found where the swarf had collected.
A while back I got a couple small UV flashlights from a bin at a big box hardware chain; they carry the logo of a formerly reputable, formerly American tool brand. They are, to all appearances, identical. One of them is your run-of-the-mill UVA purple, the other however really looks like UVC blue and makes things fluoresce real good so I don't play around with it. Or would there be a likelihood of it being UVB, which you don't hear much about?
UVB tubes are what are used for tanning beds etc
If it looks like that light Bluish colour then I wouldn’t mess wit it at all. The Purple ones are fine though.
If it has standard plastic LEDs then it's possibly that the casing is fluorescing and adding the blue look. A real UVC LED flashlight would be very expensive.
There are 395 nm and also 365 nm UV LEDs. They cause different fluorescence.
If you measure the running voltage on that "reverse connected" capacitor, you will find it is correct. When running, the transformer winding pulls the base on the BJT positive and the other end of the winding wants to go negative. The voltage will be small but the capacitor's voltage will end up negative once the thing is running.
I couldn't help but comment on the operation of the UVC fluorescent driver. What seem to be missing is the correct operation of the circuit it is a half Bridge Inverter. The inductor (typically around 4-2mH and the two capacitor 22nf and the 3n3f form a series resonant circuit. That oscillates some where around 100-60KHz. Because the tube is an open circuit at startup this heats up the filaments (current at startup is 3-4 times higher than the run current) and this also causes a high voltage around the 3n3f capacitor > 600 volts, so when the filaments are hot enough the high voltage strikes the tube causing it to be largely ohmic (i.e. a resistor). This effectively removes the 3n3f capacitor from the circuit causing the frequency to drop to around 20KHz or so. The current that now flows through the tube keeps the filament hot enough. The whole process and design of CFL lamps is explained very nicely in Philips Application Note AN99065. the side of the 22nf capacitor connect to the 340volt rail is effectively at AC ground so it could be connected the the 0 volt rail. The design in AN99065 uses a two capacitors one connected to the 340 volt rails and the other connected to the 0 volt rail. Also if you google CFL schematics and take a look at the web site by pavouk you will see lots of circuits and an explanation of the working of these inverter circuits. Its a bit hard to follow as the writer is not an native English speaker.
18:20 "...and yet they keep working..." I used to maintain the communal lighting of our appartment building and in it CFLs were used. On at dusk, off at dawn. I guesstimated 5,500 hours in operation every year. Most cfls would do 2 to 3 years that way, so way more than their advertised 6,000 or 8,000 hours (one of which managed 12 years!!! or 66,000 hours!!!). Then came the retrofit LED bulbs that would promise 15,000 or even 25,000 hours but all with a more than 470 lm rating would die very quickly, some not even reaching the lifespan of an incandescent bulb.They were baked way more inside than the CFLs. As a result I replaced them with integrated LED fixtures, some consumer ones promising only 15,000 hours and some semi-commercial ones promising 35,000 hours. They were installed in 2016 and are ALL still working perfectly today, almost 7 years later.
I noticed how you held the lamp in vice, at onetime I was doing a small production run and I needed to hold a quantity of pieces of 2 inch diameter aluminium stationary while drilling holes in the face, I put the vice in a 4 jaw chuck and machined a round face on the jaws. If you do not have access to a metal lathe possibly you could get a piece of wood and drill a 2 inch diameter hole with a hole saw and saw it through the centre and make two soft jaws, . Something to think about,
David
I know they will probably be almost impossible to get hold of and cost prohibitive, but a future video of the new 222nm far UVC lamps that are human safe would be amazing.
How's that work as 222 nm is 222 nm light ?
I'll try and get a 222nm excimer lamp at some point. I think they are still commanding a premium price due to being new. They are made by Ushio.
@@bigclivedotcom would you stare at it if it had a label that said "Human Safe" on it please ?
@@bigclivedotcom Isn't it expensive also due to the very exotic nature of the kryptom chloride compound used as the emissive medium?
The two windings on the toroid probably run the end heaters ease the arc strike. to have some fun put a bench supply across the heater and note the heater resistance is smaller than the arc across the resistance of the filament
Used to be a welder in a past life - had arc-eye a couple of times - the first (and worst) time was from a brief factory tour when I was an office boy. Had never heard of it, didn't expect it and it came on whilst I was driving home hours later in the day - not something to be recommended. Cold, used tea-bags resting on closed eyes was the recommended treatment in the day (proper teabags, I hasten to add!), no idea if it actually helped or not...
Just when you squeezed it, I thought "The vice of knowledge could be employed here"
I always feel like I’m in the room with you when watching your videos.
Also feels like you’re my good ol’ pal.
Hope you’re doing well!
Not understanding why the capacitor is apparently backwards is obviously a call for "I wonder what would happen if..." I flipped the capacitor right-way-round.
I mean, how bad could it be?
Believe it or not, that insulating wrap around the PCB is called Fish paper.
It's available at my local electronics supply house.
You've just made me realize this would be perfect for replacing the fish paper between contacts on an old slot machine.
I could smell the ozone from that lamp through the screen. Definitely should put a warning there so viewers don't look at it.
On the first PCB the electrolitic is labelled 4.7uF 250v, so I guess the 330 is the resistor value for a 120 volt version along with a bigger, lower voltage, capacitor.
Clive, you could sell a colourful album of all of your circuit photos and diagrams in a coffee table book with a small description.
I purchased a Samsung wireless charger with a uv sterilisation unit in when closed and on, it does illuminate and the light works on a timer, im unsure if it works but it was used on eBay for £1 so could not leave to rest on eBay shelves.
When in doubt, ask about, if that fails remove capacitor in question, start the camera and lets see what goes "bang"? Looking forward to that video!
The spectrum of a UV Mercury lamp is fundamentally different from LEDs. Mercury has a band spectrum meaning that besides its continuum spectrum, it has several peaks because of electron transitions. Some are in the visible region. UVC lamps must have argon too. As our brain synthesizes the sensation of color from the 3 color receptors the sensation can be the same for different spectra. But LEDs emmit on a very narrow band. There are two main UV-C LEDs the ones with Gallium-Nitrogen and the ones with Aluminuium-Gallium-Nitrogen. They usually emit at 260 or 280nm or both (this is considered more efficient in disinfection). My point is that the color means very little and the LEDs tend to have a color more akin to violet if they invade the visible spectrum. As UV-C and UV-A LEDS have a similar construction the voltage drop on them is also not an indicator. The better way is to use UV-C dosimeter cards they are created specifically to test if the device emits UV-C and tell if they are safe or dangerous and determine the exposition time to kill bacteria. They change color depending on the dosage of UV-C received.
1:17 The "exiting" part comes from the tingles that may provide the user.
This potato ritual is said to ease suffering; you can have eye drops ready, or you can use a fresh cool potato, at least as a placebo - should calm you, if not your eyes, down. ;D
I myself didn't notice much difference - after a while you get better, if only not exposed to welding sparks / harmful UV light for too long.
Thank you as always (or often) Clive, for adding to, or clarifying abstract bits of, one of my current research rabbit holes!
After learning about the medical studies on 222 nm UV being optimal for breaking microorganisms dna without penetrating human skin, I looked into all the UV bulbs available for whatever purposes and, crikey, I should have known..:::😂😂😅
¡Salud! to human engineering and the joy of our desiring to tinker with local conditions...::💎⚡💚💚💚
Don't know why but I always love that you warn viewers when the light is coming back
From Wikipedia:
UV (UV-C) considered "germicidal UV". Wavelengths between about 200 nm and 300 nm are strongly absorbed by nucleic acids. The absorbed energy can result in defects including pyrimidine dimers. These dimers can prevent replication or can prevent the expression of necessary proteins, resulting in the death or inactivation of the organism.
Mercury-based lamps operating at low vapor pressure emit UV light at the 253.7 nm line.[15]
Ultraviolet light-emitting diode (UV-C LED) lamps emit UV light at selectable wavelengths between 255 and 280 nm.[16]
Pulsed-xenon lamps emit UV light across the entire UV spectrum with a peak emission near 230 nm
I AM LOVING THE VIDEO LENGTH
Would be interesting to see some experiments with real UVC
A while back I tried the old desktop computer power supply to desktop power supply thing. It was old, so I powered it up to make sure it worked before starting. Now I had to discharge the capacitors. It was the first time I had ever done anything like that. There was a very loud bang that scared the crap out of me. My wife was in the other room and even she was startled. I decided to let it sit for 48 hours instead of doing that again.
Never short out large caps. Use a 2 watt low-R resistor to discharge the cap.
Hi Clive,
Do you know if UVC LEDs can be designed to generate ozone or is it only the tubes (With untreated quartz glass of course) that can ?
Also I'm still a lil' bit worried about the possible end of all non-LED lighting products (From halogen bulbs and fluorescent tubes for illumination to blacklight and UVC tubes).
I don't think there are commercial UVC LEDs in the 184nm region yet. It's probably cheaper and easier to do it with a corona discharge system for low output applications.
I got a UVC lamp of banggood to sterile the house to 'protect' my mum, and it following the instruction for the time for the size of room said 20 minutes, after 5 minutes the ozone smell was unbelievable and took 6 hours with all the doors and windows open for it to go 😬
Aye. I stumbled on a 55W tube unit at a thrift store for $5 with an RF remote so it can be turned on and off out of line-of-sight. It generates a huge amount of ozone. We had a mold problem in the basement and it was very helpful to keep it under control until we could get the damaged wood and drywall out.
Is really helpful though. The ozone'll kill mould, bed bugs, fleas etc etc. If you really don't like it, a 253nm UVC light is better at killing directly, and breaks down ozone faster than it creates ozone (as opposed to the 185nm, which creates ozone faster than it breaks ozone). Obviously, using it for direct sterilisation does mean it only kills on direct line-of-sight, or reflections from aluminium. Most other materials won't reflect much of the UVC. The ozone can be good to clean the bathroom, stop mould forming from humidity after a shower/bath. A timer switch could turn it on for 10 mins at night, have it fresh for the morning.
.
I’ve had flash many times. Cold wet teabags do the job and lots of whiskey (the whiskey is to drink, not for your eyes). Great video Clive and I’m still waiting for my Aliexpress delivery 😂
"The Vice of Knowledge." Classic. Reminds me of my elementary school days, when the school principal explained to the student body that if we misbehaved he "would not hesitate to apply the Board of Education to the Seat of Learning." Of course, today, he would go to jail for simply saying that.
Not "Vice" ("Immorality"), "Vise" ("Clamping tool"). Still, the idea of Knowledge as Vice is intriguing.
@@CAMacKenzie You're right about the spelling. My first mistake this year. 🤣
If only....
@@ScottGrammer Well, now that you've gotten that over with, you can relax.
@@CAMacKenzie Again, I say, "If only."
I bought these exact same lamps when the pandemic hit, you don't have a mini cob bulb, it has the most lovely ice blue I've ever seen, no uvc and super exposed voltage but it's pretty
Yeah. The ice blue lamps are very attractive. I featured them early on in the pandemic.
2.2nF cap is probably like a snubber. When the transistor turns off, it filters voltege spike over the other transistor (there is an inductor after all and it makes a spike because those switch off most probably before zero crossing). You could draw it across one transistor and it would seem more clear.
Why only one, why not one for each transistor? Because they are cheap. It is cheaper than two separate caps and there probably is enough voltage margin to get by with just one.
The effect of cap is also to help keeping the voltage zero during transistor turn off period. If current was flowing through the partially conducting transistor, it would result in switching losses when there is current flowing through a partially conducting transistor.
Things like that are quite common for resonant switching power supplies. (Or quasi-resonant like this one surely must be)
The potato juice contains starch polymers which are the ingredient in most commercial eye lubricant drops. Sounds legit to me.
I have had first hand experience of a bad flash from welding.
Basically you get a wet flannel over the eyes, lay down in a dark secluded room and scream until the next morning.
What was the phantom resistor about shown at the right hand side of the bottom PCB - after the bridge and before the caps?
Was this an "anticipated component" that was "ooooh, it's not there, ok!" :) ?
That was representing the heater in the end of the fluorescent tube.
Yay! Vice of knowledge! It's been so long since last referenced.
If at some point knowledge will be considered a vice, only outlaws will still have knowledge...
Why does this not seem totally outlandish anymore? :(
Maybe that 2.2 nF is to help with starting the oscillator?
I got a true UVC lamp (for sterilising water in fish tank filters) a couple of years back on amazon. I was dubious that it was real until I saw a one star review from someone who complained it killed all their fish... I knew I had to have it. When I turned it on and smelt the fresh ozone I knew it was the real deal.
I put it into a box lined with reflective tape and an interlock (must be closed to operate) and used it for sterilising things at the start of the pandemic, when paranoia wasn't paranoia.
I've got one of those. It's designed for the filter section of a tank and not the fish area.
Those lamps are intended for use in the filter section of large tanks.
Have you tried getting one of those UVC test cards, like quantadose?
I've not. I should get one now the pandemic price-gouging is over.
Oooooooh the special testing unit please tell me you cleaned those solder joints up?
I have the same model and get more than just a whiff of ozone when it runs. I now reflexively close my eyes whenever I see that eerie shade of aqua.
Some are optimised to produce ozone too. 254nm plus 184nm.
dont take this the wrong way clive ,but i like the longer videos !! i put them on my second monitor when i work to keep me company , short videos dont do it since i dont want to fiddle around and change videos every 5 min ,
The welders on the pipeline used milk for arc flash, couple of drops seemed to work for them
That test box where the display stays on regardless of the switch position, and then the fact you never switched it off, it was unsettling...
If you get arc flash, or snow blindness. You can uses sustain eye drops. It works for non operating mybomian glands which feels worse. Take care of your eyes.
Nice long video Clive thank you very well explained
I picked up a somewhat dubious phone sanitizer (with aromatherapy oil diffuser well heated by a power resistor!) for $5 at wally world after the hair on fire coof panic started wearing off. Really only bought it to see if it was a scam but was pleasantly surprised to find 3 actual UVC leds; it was probably still a scam since I don't see how 3 LEDs pointing at the edge of a phone could sterilize it, but technically it was emitting it. Given just the chips easily go for $2.50 a piece direct from China I should have gone back and bought 4 more before the mostly untouched pallet full was sent to the landfill or sold to a thrift store.
This is what happens when you send away the professional telephone sanitizers on the same ark as the account executives.
I just bought a 5€ Philips HP3112 sunlamp from 1962. It has two danger modes: 1 if you flick to switch to UV+IR and 2: if you break the mercury tube.
I have one here waiting a video.
I tend to watch the longer videos over a day or two. No idea how that shows for your metrics but I love the meaty videos.
Always nice to see you taking the Death Box out for a spin. ;)
How much roughly do regular eye glasses protect your eyes from uvc? Is it safe enough to leave the light on while in the room or is it still necessary to leave asap? Can too much ozone be harmful if I leave the uvc light on overnight to sanitize/sterilize my kitchen for example? I have little to no airflow from my kitchen to my bed room due to how my apartment is ventilated.
Glasses will block direct UVC but not reflections from the sides. I don't recommend staying in a room with a lit UVC lamp.
@@Okurka. Are you really that ignorant that you think I would not first clean "normally" before using uvc radiation and ozone? Do not answer just to keep your keyboard buissy, think first.
@@Okurka. You made a assumption about me that you have neither the knowledge or basis to make as you do not know me at all. You insulted me and my character with no cause or right, so FU*K YOU to.
I've got 30w uvc for pond helps get rid of alge clear tube sits inside exspensive quartz tube in which pond water flows round,tubes sat inside larger plastic cylinder.which also gives good protection to eyes, Had to replace quartz tube once3' cost around £30.
Where would you suggest buying UVC lamps from?
The AliExpress quartz tube ones are real.
The 2.2 cap might be to soften the initial surge.