The 'FU' resistor looks like something that happens frequently when a prototype is handed over for production. People who don't properly understand the circuit often make stupid 'improvements' that essentially delete necessary functions. About 40 years ago I worked in a high energy physics lab. My job, fresh out of university, was to develop a box of electronics to go inside an accelerator. I won't go into detail about what the box did, what is important is that the environment it had to endure was extremely hostile. There were physical, chemical, electrical and radioactive properties that were all conspiring to kill off this relatively simple little telemetry box. The first prototype lasted only a few minutes before failing. After four re-designs I had a prototype that would last months rather than minutes. At this point I began to prepare the design for the production of about 50 units. Before that was completed, I moved to a new job. About six months later I got a call from my old lab. The production boxes were failing after only a day or two but my original prototypes were still working fine. It turns out that the numbskull who designed the PCB saw what he thought were 'redundant' or 'pointless' components and summarily deleted them from the layout. What he had done was to remove all the over-voltage, RF and reverse polarity protection. He also replaced critical components with cheaper alternatives that were not rated for the environment.
A relative was a retired barber, he had a white cabinet that held his tools and it had this very bulb shining down on the barber’s instruments, you could look straight at it. ( for 50 years i thought it was a fake uv lamp). now I understand it was real, ( and slightly dangerous) Clive; thanks so much for setting me straight.
The laundry at the hospital I used to work at had those UV germicidal lamps....they had a fairly long life. I don't remember changing many of them...the dryer and sheet folder had them, as I recall. The sheet folder was called a " mangler", and it often lived up to the name.
The tubes are supposed to be changed routinely. The quartz/uviol glass changes state over time under the exposure to the UVC and gradually reduces its output. They still look visually as bright though.
Perhaps the intended options were to use the existing setup without the FU link or non-rechargeable batteries without the rest of the charging circuit. By the time it got to production nobody remembered that the FU link should be omitted.
Yes and when the final schematic was made someone just ticked both options. Honestly likely, I work for a machine manufacturer and the most common reason for errors like that is conflicting options selected as active or incorrect one versus the physical layout.
I suspect this is a BOM error. I bet they were supposed to load either the two diodes or the zero ohm resistor. If you load the diodes you can power directly off of USB. If you don't, you have to charge the batteries first.
But you could just place the link instead of the second Schottky diode if you wanted that. There's no need for the additional track and pair of solder pads.
I really enjoy watching you reverse-engineer electronics. My dad was an electronics engineer, and when I was a kid, he taught me how to build circuit boards and help with his various inventions(he worked for RCA). He took the view that girls were allowed to learn whatever interested them, back in the Qq1950s. He taught me about holograms and microwave technology while I soldered simple circuits at the age of 7. While my mom was more traditional, he was fully in support of me majoring in chemistry and physics at uni. When I wanted a crystal radio kit (one of those kits you just plug components together), he said, no, let me teach you how to build one yourself! Fun times!
It's was fine out here. No one fell for it. I can't believe that some people are still walking around with those germ collectors on their faces. They must watch CNN.
I think something was attempted that was called "a joke". Sadly, "jokes" are an endangered species due to people over analysing them and not leaving them alone to breathe. If you find yourself analysing a "joke", or it's similarly endangered cousin the "humourous utterance", you may be committing murder!
@@robertwilloughby8050 The humorous utterance must be at least a dozen times rarer than the standard stated joke. There are not enough whoooshes!! in all the world to keep them safe from all the language trolls.. ☺
This reminds me so much of the misery of using The Art of Electronics as an undergraduate textbook. It's poor book to teach from but a fabulous bench reference. Periodically, they'd include pages of schematics of bad circuits with no explanation, leaving the poor reader to sort them out on their own. I wish every bad circuit in Horowitz & Hill had this level of explanation; reverse engineering is such a useful skill, I really don't know of a better way to learn than watching you dissect some poor eBay device and make surprised and appalled noises.
Making any equipment that uses UVC out of plastic seems like a really bad idea... But the "charge a protected lithium cell from USB with only a diode" was (and still is?) quite common in small portable media players. I suspect the designer might've originally used the charger IC and diodes, then discovered that trick and added the link, but forgot to remove the other components.
I bought two of these in 2020 and they shipped three. None of mine have batteries inside- but have a sticker on the bottom that says they are rechargeable. The PC boards inside don’t even have the sockets for the batteries, they just run directly from the micro USB connection. eBay always ceases to impress, LOL.
Really clever little schematics apart from the FU like. I can understand your enjoyment at spotting it.🤣 I still find it wonderful that so many new products are coming out, can you imagine getting this when we were kids it would be on Tomorrow's World.
I've got something like this - but there's 2 lights, and a triangular heating element, to go in wet trainers to dry them out. I seem to remember both sides lighting up - AC from the DC USB plug... nicely done!
Well done. Simon, there's a flat wire that you can buy especially to draw wires from the front to the back. I always pulled my wires in the car beems or where ever I could get it. The piping is alright just thick. Love the videos.
Currently, the major commercial GaN FETs are lateral high-electron-mobility transistors (HEMTs). These GaN switching devices come in two different types: enhancement mode (e-GaN) and depletion mode (d- GaN).
FU links like that are what keep me up at night. How many ultra low cost consumer products have little oopsies like that in them, very easy mistake to make, even large reputable companies do it in expensive products occasionally. I hope at least that link causes most USB power supplies to trip OCP when you plug them in when very discharged, you'd at least maybe get some warning there was something wrong with it. Considering they placed both the link and the diodes and it doesn't look like a manual hand bodge I would assume there was some mix-up with the PCB assembler who just populated everything instead of config A *OR* config B and the customer just sent the batch off for sale and the original circuit designer wasn't retained for QC consulting.
I was just messing around with one of those bulbs. fired up 1 electrode as well with a $3 dollar buck boost with a 1.3v to 24v and a bit of voltage lowering from 15v strike and 12.5v once the plasma is struck.
@@bigclivedotcomI actually remember running across some UV lamps that were essentially like incandescent bulbs here in United States years and years ago Hollywood vintage equipment don't remember when they use these or anything like that I know that they had used some in Old refrigerators years ago also have red as well as seen on mine about things like this unfortunately can't put my finger on a date when things like this would have been done by now it was quite far back. The interesting thing is when you would use so many bulbs the UV Bolton is not sure if it could be done for single bulb or not I do know that at one point that sometimes incandescent bulbs were used as ballast for these lamps apparently was quite a common practice back in the day I don't know if these were designed a differently from these type of lamps featured in the video and the others you've done on these products and the and do UV lamps themselves there were a couple different styles with ease and at least one of them was produced later on still as well. I know people that had these little boxes that were like integrated into something else and I noticed air blowing through them and ask for the word I said oh it's a air sanitizer or something like that turns out that's what these were using was one or more UV bulbs I noticed some that had a way to actually convert the uve to visible light into also act as a night light I have not seen this before but it was interesting and they said they had them on 24/7 and had to replace the bulbs every so often apparently were popular in bathrooms at one point I did also see it vintage thing that was like this as well but also had little compartments for toothbrushes I guess would also be not only dares sanitizer but a toothbrush sanitizer it was just online for both interesting Lee enough also had that feature to convert uv2 visible light and passed some of the blue glow as well at believe so kind of a try use device but interesting nonetheless clearly design for bathroom pretty clever not sure exactly how well these lamps work with actually sanitize a year or even just less messy Andorra fluted or otherwise I would not probably exactly call it is sterilized Airforce a however in the refrigerators I did hear that it did make some difference not just of odors but better life of fruits and vegetables in the fridge come to think of it I think these lamps I'm referring to were referred to as ozone lamps as well but probably also was doing some Eevee type cleaning as well loves the air and other services. Also I was working at thrift store and also got a program if you want to call it that going for taking care of mercury waste such as fluorescent use germicidal tubes or anything that would clearly have mercury in it that was going to be disposed of such as a device that did not work and was heading for the compactor. Protocol was in place to check for mercury warning and it's also applied got this going as well with rechargeable batteries not just lithium batteries obviously with the lithium batteries that could be a big problem with everything basically hits the trash compactor that is disposed of or at least when it's possible to get in there obviously there's a few things that when you go into the compactor. Also we had a few fires that place two in one day even once and we also had a vehicle fire once! Needless to say they're aware that I had had fire training before for various reasons and if ever needed to be assisted with using fire extinguishers get ahold of me for sure if I was available. Menu time in my life I've used a fire extinguisher nothing that was my fault need to use it either but things others had done or something went haywire or otherwise. Even a few times using the fire hose as well. Had training on this because of various things I've done over the years. It's a good skills to know how to properly snuff out to properly use equipment like this and can be life-saving. Was thinking school.law safety training with was stage crew because there's a lot of Hazards and some of these people don't realize what can happen and all the hazards involved. It was said that oftentimes Stage production can be more dangerous than football. For the most part you don't have hundreds of amps and more of electrical power in some cases stuff you would normally not run across and day-to-day use with electrical hookups some of these were necessary because of lack of proper connections and the means will head to use to actually connect equipment. By the way did wind up becoming the literal stage crew electrician! Everyone in school and everywhere else even School Board realize that I was her she qualified to do things like this even though I'm not certified. I was wandering around school that was off and doing repairs and much more. Ashley had a few job offers after I got out of school to work for various areas in the school. I was also maintaining equipment even doing stuff in class that was actually more of maintaining and repair than actual class work even in the shop classes I was hit I was doing a lot of repair work the maintaining equipment. And yes I was the one that was allowed to borrow tools and such from the school if ever need me for anything at all shop teacher actually was the one that brought this up that after he got everything except for log other things that I didn't realize that we're going in the background with me as well. I didn't even realize I was actually being graded for extra credit with anything else I was doing outside of my school work 4 things as well anything that would be considered outside of it was considered a project for school! I did not know this is going on for quite a while and he said hey nice work looks like an A+ to me and then he sprung it on me pretty cool! Didn't even really need extra credit but it was there! Interesting. Our school is that if things would work for it imperious way is in things could be applied to different classes for the same project kind of met something along the lines of that class you can get credit for a project in more than one class. For example the written part of a project could go toward English or otherwise classes credit write down if you had typed this up on computer for example that could go to that class as well. Kind of weird but rather interesting and there's times that I had wanted to do something even just experimenting lie horse one posed a question or I get myself and when the science teachers would let me know that hey you know it be an interesting experiment to actually do something and find out one way or the other. I was so active in my classes that and people realize that way to Sac even commenting on things that I'd said in said and had even influenced things brighten up in that class so that you do the further things of interest to others as well as well as go further into some topics. This is right down to history class and much more even going further in science classes in such. I found out from someone old teachers at schools this and actually dog further in led into much more content for the students as well as the rich bitter class participation my teacher said that I have made a big difference in sometimes with this and it was always encouraged. I was so far ahead that I had down time and was able to do things on the side for my own benefit essentially making my own extracurriculars you could say a lot of this was technology and all related I was warming skills that they didn't even teach our school that they brought in outside resources to help with this also to cut down on boredom in school essentially I could take a pretest and test out of things and be able to do other things that might be better used for myself as long as it gave me some time to just the more myself and learn things that might not have otherwise when people realize when the student has potential and nurtures this and is able to go outside of the usual box I had access to all sorts of things that most students with. There are very few. I did have legitimate reasons to have access to some things as well as there's times that I would actually need to go to the cafeteria between normal times did also have access to vending when needed I did actually have my own so the keys everything was legit some of which I need access to for certain reasons part of which was stage crew as well also that means that I could fix problems when things occurred as well and yes we would be Moonlighting on maintenance and otherwise as well never was well sometimes I'd even sometimes even be taken out to lunch or something like that as well or perhaps yellow Subway had something that was no longer needed but couldn't use for something that sort of thing it was just part of doing things outside of the box you can say
And honestly, I am pretty sure that the diode that they have, would be able to handle the current just fine, and if anything, that link that they put in, can just be chopped out, and heck even replaced with another diode of the same rating roughly, tho would be different size probably if you don't want to do some semi~odd stuff to attach a same size same type diode onto smaller pads than it's meant for.
I’ve got a humidifier with a GTL 3 lamp in it. It’s got an LED to indicate that the lamp is working that presumably just senses current through it. I’m going to have to pull that apart sometime to have a look at the driver they’re using.
My electronics knowledge is hobbyist at best, but wouldn't running the lamp on DC cause it to polarize and reduce its life? Or is that for HV DC mercury lamps? Excellent video as always, thank you.
Not on lamps this small. That is more an issue with fluorescent lamps that are very long relative to their diameter where the mercury is pulled to one end faster than it can diffuse back.
@@alunjones3860 That would be the main issue, but would this degradation happen faster than the photodegradation of the envelope glass? That would be an interesting test, actually.
Could it be that the mysterious 100K resistor is used to pull down the gate of the buffer MOSFET inside the microcontroller? It is unlikely though because such resistior would normally be inside the IC.
I was looking forward to the reason why Clive was laughing, and it did not disappoint, when he added the link to the schematic I absolutely cracked up.
My wife and I check the local thrift store today and I found an old hearing aid sanitizer, never used. Made me think of you, Has a mercury UV-C lamp with a 24 volt supply. Got it for $5. I wish I could send it to you but I am in the US...
I made an EPROM eraser with one of those GTL3 bulbs. I found a circuit that used a 6 uF capacitor in series with it that works with 120 volt mains. Nothing fancy, but it does a good job.
Nice score Clive. 3 Li batteries. How bizarre, the circuit, and 'cage'. The slots suggest movement, rotation ?! Zebra Stripe Tanning, come one come all... ;)
I wonder if those still learning the basics of how switch-mode converters work might find it easier to understand what the inductor is doing if it was explained in terms of current rather than voltage? The current in the inductor cannot simply stop when the MOSFET switches off - the energy in the magnetic field continues to drive it in the same direction - it is this that produces the rise in voltage. Self-inductance is analogous to momentum if you like to think of electricity in terms of water flowing in pipes where voltage becomes pressure, current is litres per second and capacitors are tanks.
I have some ASE3WE17 I bought back in early 2020 to make a UVC box, even got the AC power supply but just never got around to making the box. Found out the UVC can age plastics really quickly so didn't wanna risk my phone falling apart, even if it was germ free.
Could fix this design, and improve on the Schottky diode current problem, by just putting a second diode across that link. They won't be perfectly matched, but the safety factor will be back, and you'll have better current handling. Personally, I'd want to build an H-bridge driver for that lamp. It annoys my OCD that only half the filament is lighting up. 😅🤪😵💫👍
If the link was not there, both the Vin and Vout pins of the chip would be one schottky diode drop above the +V rail of the rest of the circuit. In other words, at the same potential. I think the circuit "designer" painted themself into a corner and couldn't think of any other way out.
can we expect shorter bulb life on dc? few years ago i tried a 555 at 12v/1khz big cap in series to give some fake ac but never got it to work. was trying to put it in a 12v fridge
@@albanana683 The link is still redundant, since that's what diodes which get too hot generally turn into. At currents like here you won't even see smoke, it's not that much current.
To me it feels like the designer of the board only intended for the 'FU' link to be populated if neither of the diodes were populated... but their intentions got lost somewhere on the way to production.
I was expecting the test card to confirm the UVC. Have you put them somewhere safe? You know: "I'll put them somewhere safe so I know where they are the next time I want to use them".
I have a UvC shoe sterilizer from Amazon that uses that same bulb. Only problem with it is the bulbs seem to rattle loose easily. Idk if it has the FU resistor though
I don't understand the F-Link but the way they designed the circuit board reminds me of being in my late 20s in 1986 and getting to use circuit board layout on CAD. I used to do some layouts with black tracer tape on clear acetate film 2x to be reduced by the board manufacturers years before at another company. The program was called P-Cad and we had a new 386 computer with a huge 40MB hard drive! Nowdays people can't believe it. Autorouting was fascinating to watch on the 14" CRT monitor too! Shit, I am not THAT old...
If they were concerned about voltage drop I wonder if they could have used a mosfet set up to be on with a grounded gate and pulled the gate down to ground with a resistor and then connected it to the positive USB rail
Did you think of taking out the FU link and see if it would work ok? And also wanted say love all ya video's 💯% I like reverse engineering but never thought of putting all the work in that you do.. all I can say is just Thanks
All of my UV-C bulbs make a smell after running but they don't smell like ozone to me. It's more of a burnt smell and I can't decide what it is. My "reference" for what ozone smells like is a discharge from a crt flyback transformer. I've also worked with higher current discharges that are capable of making NO so I know what that smells like as well. Any ideas on what's going on?
Hmm, now you have me wondering. I thought the ionized air around a TV flyback transformer had a slightly sweet smell, while the ozone generator in the records room where I used to work had a similar but more acrid smell. I’m not sure which, if either, was more purely ozone.
@@SianaGearz Indeed, in my experience UVC lamps make skin smell a bit burnt. The ionizing radiation breaks down molecules on the surface and accelerates oxidation.
UVC is such a short wavelength that it doesn't penetrate deep into the dermal layer. It will cause skin irritation with time, but is much more likely to cause temporary eye surface discomfort in the same way that arc welding exposure does. The discomfort usually happens at night as a temporary sensation of having sand in your eyes.
Chinese Manager: Copy this thing! Chinese Minion: YES SIR!! It says 0R on the silkscreen so better put that one in without thinking too much Maybe that is the option for an external 4,2v charger or something
In the case of these lamps it's recommended to clean them after handling to avoid oils blocking the UVC. For quartz halogen lamps it's to avoid oils that will devitrify the quartz at the high temperatures save cause it to fail.
I recall the same instruction. If I recall it was intended for bulbs that burned very hot and any contaminants on the glass surface might cause the glass to shatter. I recall the same instructions were given for halogen lamps, slide and movie projector (remember them?), etc...
What do the designers know? That diode was clearly just unnecessary fluff! (I'm obviously joking since they spent more on the wasted charge controller than the diode.)
Little brother robot entering the house. "Wow. What's that bright purple light lighting up Grandpa's window?" Big sister robot "It's his new tanning lamp." \ / #:-) &:-) ---- 8o] ---- / \
My work phone (cubot j3 ) keeps puffing batteries. So as it lives in the car during use. I was thinking replacing the battery with a USB lead adding a resistor to the t terminal and maybe putting a diode on the 5v to drop it a little bit. Plan b is attach a 18650 battery holder to the case and connect that in with a t resistor . Either way it's my fu link to avoid buying another pillow battery and not make the cracked screen any worse. (I'm avoiding changing the phone as the work software is older version that does not autoupdate , I have the apk file but it doesn't pass on other phone)
@@bigclivedotcomphone does get hot I protect it from sunlight, the software is tough on the phone . Some days moreso than others , I think it's when customers check location it increases communication. GPS and wifi (no sim) I have a 10A 5v supply, (12v input chunk of metal size of pack of cigs )runs dashcam relentlessly. Not sure of sensible way to loose 0.8v or if it's even something I should be concerned about.
Birth quartz, but the extreme heat of the halogen causes issues with finger oils causing devitrification of the quartz. With UVC, finger oils may partially block output.
I don't own a single screwdriver with that funny looking insulation on it. I wonder if it's a European standard, because I first saw them on channels like yours or Techmoan's. What is the purpose of the insulation? If it's a good enough reason, I would consider retrofitting my existing drivers.
@@bigclivedotcom Ahhh thanks, that's what I needed. So it seems there's more to them than just the rubber coating. Maybe I should get a set, for when I'm working on high voltage tube based equipment.
The 'FU' resistor looks like something that happens frequently when a prototype is handed over for production. People who don't properly understand the circuit often make stupid 'improvements' that essentially delete necessary functions. About 40 years ago I worked in a high energy physics lab. My job, fresh out of university, was to develop a box of electronics to go inside an accelerator. I won't go into detail about what the box did, what is important is that the environment it had to endure was extremely hostile. There were physical, chemical, electrical and radioactive properties that were all conspiring to kill off this relatively simple little telemetry box. The first prototype lasted only a few minutes before failing. After four re-designs I had a prototype that would last months rather than minutes. At this point I began to prepare the design for the production of about 50 units. Before that was completed, I moved to a new job. About six months later I got a call from my old lab. The production boxes were failing after only a day or two but my original prototypes were still working fine. It turns out that the numbskull who designed the PCB saw what he thought were 'redundant' or 'pointless' components and summarily deleted them from the layout. What he had done was to remove all the over-voltage, RF and reverse polarity protection. He also replaced critical components with cheaper alternatives that were not rated for the environment.
Been there
An example of "false economy". Save a little by omitting some components, but over time end up paying out a lot more due to the unit rapidly failing.
that designer sounds like the person who knows everything better xD we all have one of thos
Why would they call you up after the fact to tell you that and not just go back to the design that worked?
@@phonotical Stupidity and arrogance.
This fully complies with BCDC standards of danger. 3x lithium fire risk and cancer rays plus bonus comedy circuitry.
A relative was a retired barber, he had a white cabinet that held his tools and it had this very bulb shining down on the barber’s instruments, you could look straight at it. ( for 50 years i thought it was a fake uv lamp). now I understand it was real, ( and slightly dangerous)
Clive;
thanks so much for setting me straight.
The laundry at the hospital I used to work at had those UV germicidal lamps....they had a fairly long life. I don't remember changing many of them...the dryer and sheet folder had them, as I recall. The sheet folder was called a " mangler", and it often lived up to the name.
The tubes are supposed to be changed routinely. The quartz/uviol glass changes state over time under the exposure to the UVC and gradually reduces its output. They still look visually as bright though.
@@bigclivedotcom Planned obsolescence or unavoidable side-effect..?
@@scottthomas3792 That's alright, placebo still works like ~30% of the time, right?
Let's all just take a moment to appreciate the biblical amount of printer ink that Big Clive must churn through!!
Bulk ink system.
@@harikrishna69 that's a rather personal request 😂
@@harikrishna69 It's a standard Epson ecotank these days. It used to be an external tank hack.
I gave up on printer ink years ago. It's all about the lasers now. 😊
@@crazygeorgelincoln Laser printers are great until you need to print a photo or anything else with fine detail...
Perhaps the intended options were to use the existing setup without the FU link or non-rechargeable batteries without the rest of the charging circuit. By the time it got to production nobody remembered that the FU link should be omitted.
They could have easily made this circuit honest by adding one P-channel MOSFET and a resistor.
Yes and when the final schematic was made someone just ticked both options.
Honestly likely, I work for a machine manufacturer and the most common reason for errors like that is conflicting options selected as active or incorrect one versus the physical layout.
The FU link was maybe on purpose. To FU owner of the company.
I suspect this is a BOM error. I bet they were supposed to load either the two diodes or the zero ohm resistor. If you load the diodes you can power directly off of USB. If you don't, you have to charge the batteries first.
But you could just place the link instead of the second Schottky diode if you wanted that. There's no need for the additional track and pair of solder pads.
I really enjoy watching you reverse-engineer electronics. My dad was an electronics engineer, and when I was a kid, he taught me how to build circuit boards and help with his various inventions(he worked for RCA). He took the view that girls were allowed to learn whatever interested them, back in the Qq1950s. He taught me about holograms and microwave technology while I soldered simple circuits at the age of 7.
While my mom was more traditional, he was fully in support of me majoring in chemistry and physics at uni.
When I wanted a crystal radio kit (one of those kits you just plug components together), he said, no, let me teach you how to build one yourself! Fun times!
You must be over 80 now.
@@hop-skip-ouch8798 Well, that was somewhat rude.
did you choose to have a career or a family?
@@hop-skip-ouch8798 eg I was born in 51, 7 in 58, equals a young 72.
@@tony_w839 Ah yes. For some reason I assumed she was 7 at 1950.
The pandemic sucked for everyone except the guy with the warehouse full of vintage germicidal bulbs
It's was fine out here. No one fell for it. I can't believe that some people are still walking around with those germ collectors on their faces. They must watch CNN.
@@Okurka. critical thinking isn't for everyone apparently, maybe keep your ideas to yourself
@@bingusdingus8239 same could be said to you. Have a nice day
I think something was attempted that was called "a joke". Sadly, "jokes" are an endangered species due to people over analysing them and not leaving them alone to breathe. If you find yourself analysing a "joke", or it's similarly endangered cousin the "humourous utterance", you may be committing murder!
@@robertwilloughby8050 The humorous utterance must be at least a dozen times rarer than the standard stated joke. There are not enough whoooshes!! in all the world to keep them safe from all the language trolls.. ☺
This reminds me so much of the misery of using The Art of Electronics as an undergraduate textbook. It's poor book to teach from but a fabulous bench reference. Periodically, they'd include pages of schematics of bad circuits with no explanation, leaving the poor reader to sort them out on their own. I wish every bad circuit in Horowitz & Hill had this level of explanation; reverse engineering is such a useful skill, I really don't know of a better way to learn than watching you dissect some poor eBay device and make surprised and appalled noises.
This is what happens when a warehouse cleans out the back corner filled with old lamps & FU links :)
Making any equipment that uses UVC out of plastic seems like a really bad idea...
But the "charge a protected lithium cell from USB with only a diode" was (and still is?) quite common in small portable media players. I suspect the designer might've originally used the charger IC and diodes, then discovered that trick and added the link, but forgot to remove the other components.
I have a feeling they had a ton of left over boards from something else and just re-used them for this product... Fairly common Chinese practice.
I love his excitement when he pulls something apart that’s different or weird.
7:42: Clive: "They put the link option in there and then built the link."
You should have 3 million subs, such a good dude.
I bought two of these in 2020 and they shipped three. None of mine have batteries inside- but have a sticker on the bottom that says they are rechargeable. The PC boards inside don’t even have the sockets for the batteries, they just run directly from the micro USB connection. eBay always ceases to impress, LOL.
You are an expert in electronics and finding weird stuff, great job, it is always interesting and entertaining
Really clever little schematics apart from the FU like. I can understand your enjoyment at spotting it.🤣 I still find it wonderful that so many new products are coming out, can you imagine getting this when we were kids it would be on Tomorrow's World.
I've got something like this - but there's 2 lights, and a triangular heating element, to go in wet trainers to dry them out. I seem to remember both sides lighting up - AC from the DC USB plug... nicely done!
You had me at "hideous design feature".
Well done. Simon, there's a flat wire that you can buy especially to draw wires from the front to the back. I always pulled my wires in the car beems or where ever I could get it. The piping is alright just thick. Love the videos.
Currently, the major commercial GaN FETs are lateral high-electron-mobility transistors (HEMTs). These GaN switching devices come in two different types: enhancement mode (e-GaN) and depletion mode (d- GaN).
1) Did you remove the 0 ohm resistor (later on, to see if it still works)?
2) Did you test this lamp on your new UV card and see how well it performs?
FU links like that are what keep me up at night. How many ultra low cost consumer products have little oopsies like that in them, very easy mistake to make, even large reputable companies do it in expensive products occasionally. I hope at least that link causes most USB power supplies to trip OCP when you plug them in when very discharged, you'd at least maybe get some warning there was something wrong with it.
Considering they placed both the link and the diodes and it doesn't look like a manual hand bodge I would assume there was some mix-up with the PCB assembler who just populated everything instead of config A *OR* config B and the customer just sent the batch off for sale and the original circuit designer wasn't retained for QC consulting.
Move the material from the earth to the landfill and make as much money as possible in between. The rest is of consequence only to the future.
I was just messing around with one of those bulbs. fired up 1 electrode as well with a $3 dollar buck boost with a 1.3v to 24v and a bit of voltage lowering from 15v strike and 12.5v once the plasma is struck.
seeing you laugh brings me joy
I havent studied electonics at all but I've watched so many of your videos I understand everything youre saying its wild
It's the best and easiest way to learn.
@@bigclivedotcomI actually remember running across some UV lamps that were essentially like incandescent bulbs here in United States years and years ago Hollywood vintage equipment don't remember when they use these or anything like that I know that they had used some in Old refrigerators years ago also have red as well as seen on mine about things like this unfortunately can't put my finger on a date when things like this would have been done by now it was quite far back.
The interesting thing is when you would use so many bulbs the UV Bolton is not sure if it could be done for single bulb or not I do know that at one point that sometimes incandescent bulbs were used as ballast for these lamps apparently was quite a common practice back in the day I don't know if these were designed a differently from these type of lamps featured in the video and the others you've done on these products and the and do UV lamps themselves there were a couple different styles with ease and at least one of them was produced later on still as well.
I know people that had these little boxes that were like integrated into something else and I noticed air blowing through them and ask for the word I said oh it's a air sanitizer or something like that turns out that's what these were using was one or more UV bulbs I noticed some that had a way to actually convert the uve to visible light into also act as a night light I have not seen this before but it was interesting and they said they had them on 24/7 and had to replace the bulbs every so often apparently were popular in bathrooms at one point I did also see it vintage thing that was like this as well but also had little compartments for toothbrushes I guess would also be not only dares sanitizer but a toothbrush sanitizer it was just online for both interesting Lee enough also had that feature to convert uv2 visible light and passed some of the blue glow as well at believe so kind of a try use device but interesting nonetheless clearly design for bathroom pretty clever not sure exactly how well these lamps work with actually sanitize a year or even just less messy Andorra fluted or otherwise I would not probably exactly call it is sterilized Airforce a however in the refrigerators I did hear that it did make some difference not just of odors but better life of fruits and vegetables in the fridge come to think of it I think these lamps I'm referring to were referred to as ozone lamps as well but probably also was doing some Eevee type cleaning as well loves the air and other services.
Also I was working at thrift store and also got a program if you want to call it that going for taking care of mercury waste such as fluorescent use germicidal tubes or anything that would clearly have mercury in it that was going to be disposed of such as a device that did not work and was heading for the compactor.
Protocol was in place to check for mercury warning and it's also applied got this going as well with rechargeable batteries not just lithium batteries obviously with the lithium batteries that could be a big problem with everything basically hits the trash compactor that is disposed of or at least when it's possible to get in there obviously there's a few things that when you go into the compactor.
Also we had a few fires that place two in one day even once and we also had a vehicle fire once!
Needless to say they're aware that I had had fire training before for various reasons and if ever needed to be assisted with using fire extinguishers get ahold of me for sure if I was available.
Menu time in my life I've used a fire extinguisher nothing that was my fault need to use it either but things others had done or something went haywire or otherwise.
Even a few times using the fire hose as well.
Had training on this because of various things I've done over the years.
It's a good skills to know how to properly snuff out to properly use equipment like this and can be life-saving.
Was thinking school.law safety training with was stage crew because there's a lot of Hazards and some of these people don't realize what can happen and all the hazards involved.
It was said that oftentimes Stage production can be more dangerous than football.
For the most part you don't have hundreds of amps and more of electrical power in some cases stuff you would normally not run across and day-to-day use with electrical hookups some of these were necessary because of lack of proper connections and the means will head to use to actually connect equipment.
By the way did wind up becoming the literal stage crew electrician!
Everyone in school and everywhere else even School Board realize that I was her she qualified to do things like this even though I'm not certified.
I was wandering around school that was off and doing repairs and much more.
Ashley had a few job offers after I got out of school to work for various areas in the school.
I was also maintaining equipment even doing stuff in class that was actually more of maintaining and repair than actual class work even in the shop classes I was hit I was doing a lot of repair work the maintaining equipment.
And yes I was the one that was allowed to borrow tools and such from the school if ever need me for anything at all shop teacher actually was the one that brought this up that after he got everything except for log other things that I didn't realize that we're going in the background with me as well.
I didn't even realize I was actually being graded for extra credit with anything else I was doing outside of my school work 4 things as well anything that would be considered outside of it was considered a project for school!
I did not know this is going on for quite a while and he said hey nice work looks like an A+ to me and then he sprung it on me pretty cool!
Didn't even really need extra credit but it was there!
Interesting. Our school is that if things would work for it imperious way is in things could be applied to different classes for the same project kind of met something along the lines of that class you can get credit for a project in more than one class.
For example the written part of a project could go toward English or otherwise classes credit write down if you had typed this up on computer for example that could go to that class as well.
Kind of weird but rather interesting and there's times that I had wanted to do something even just experimenting lie horse one posed a question or I get myself and when the science teachers would let me know that hey you know it be an interesting experiment to actually do something and find out one way or the other.
I was so active in my classes that and people realize that way to Sac even commenting on things that I'd said in said and had even influenced things brighten up in that class so that you do the further things of interest to others as well as well as go further into some topics.
This is right down to history class and much more even going further in science classes in such.
I found out from someone old teachers at schools this and actually dog further in led into much more content for the students as well as the rich bitter class participation my teacher said that I have made a big difference in sometimes with this and it was always encouraged.
I was so far ahead that I had down time and was able to do things on the side for my own benefit essentially making my own extracurriculars you could say a lot of this was technology and all related I was warming skills that they didn't even teach our school that they brought in outside resources to help with this also to cut down on boredom in school essentially I could take a pretest and test out of things and be able to do other things that might be better used for myself as long as it gave me some time to just the more myself and learn things that might not have otherwise when people realize when the student has potential and nurtures this and is able to go outside of the usual box
I had access to all sorts of things that most students with. There are very few.
I did have legitimate reasons to have access to some things as well as there's times that I would actually need to go to the cafeteria between normal times did also have access to vending when needed I did actually have my own so the keys everything was legit some of which I need access to for certain reasons part of which was stage crew as well also that means that I could fix problems when things occurred as well and yes we would be Moonlighting on maintenance and otherwise as well never was well sometimes I'd even sometimes even be taken out to lunch or something like that as well or perhaps yellow Subway had something that was no longer needed but couldn't use for something that sort of thing it was just part of doing things outside of the box you can say
I love learning from the mistakes these designers or builders make, some of them are real head-scratchers.
@@Okurka. fk'd up?
THAT looks like something really fun for an experiment or two =) Very informative as always, looking forward to the next video!
People: dead-afraid of the tiniest bit of radioactivity.
Also people: Oh yeah, just beam that UV-C everywhere 🤣
Content free comment to drive engagement for my favorite channels
And honestly, I am pretty sure that the diode that they have, would be able to handle the current just fine, and if anything, that link that they put in, can just be chopped out, and heck even replaced with another diode of the same rating roughly, tho would be different size probably if you don't want to do some semi~odd stuff to attach a same size same type diode onto smaller pads than it's meant for.
8:46 The COMP pin is for control loop compensation; a bit strange to have only a capacitor there, and no resistor.
I’ve got a humidifier with a GTL 3 lamp in it. It’s got an LED to indicate that the lamp is working that presumably just senses current through it. I’m going to have to pull that apart sometime to have a look at the driver they’re using.
My electronics knowledge is hobbyist at best, but wouldn't running the lamp on DC cause it to polarize and reduce its life? Or is that for HV DC mercury lamps?
Excellent video as always, thank you.
Not on lamps this small. That is more an issue with fluorescent lamps that are very long relative to their diameter where the mercury is pulled to one end faster than it can diffuse back.
@@randacnam7321 thank you. As I mentioned, hobbyist at best :)
@@keithmower921 a valid question
Running off DC does shorten the life of the lamp, because only one electrode glows. AC spreads the wear over both electrodes.
@@alunjones3860 That would be the main issue, but would this degradation happen faster than the photodegradation of the envelope glass? That would be an interesting test, actually.
Could it be that the mysterious 100K resistor is used to pull down the gate of the buffer MOSFET inside the microcontroller? It is unlikely though because such resistior would normally be inside the IC.
I was looking forward to the reason why Clive was laughing, and it did not disappoint, when he added the link to the schematic I absolutely cracked up.
2:09, the abject JOY in the Voice. the brain ''Pinged'' and you hear the Joy. LOL
btw, I was like number 209. just spooky possums.
Looks a good lamp to have hanging about, thanks Clive I enjoyed your laugh, when I hear that laugh I know it’s going to be fun 😊
My wife and I check the local thrift store today and I found an old hearing aid sanitizer, never used. Made me think of you, Has a mercury UV-C lamp with a 24 volt supply. Got it for $5. I wish I could send it to you but I am in the US...
I made an EPROM eraser with one of those GTL3 bulbs. I found a circuit that used a 6 uF capacitor in series with it that works with 120 volt mains. Nothing fancy, but it does a good job.
Make sure you use a discharge resistor across the capacitor, as otherwise the pins of the plug can give you a nasty zap when unplugged.
I bought something similar to this from Amazon for a tenner. I use it to wipe EPROMs. Quite surprised it works as well as it does for the price!
ME: fu link? do you mean a fusible link?
BC: i suppose it might but no. 😆
Nice score Clive. 3 Li batteries. How bizarre, the circuit, and 'cage'. The slots suggest movement, rotation ?!
Zebra Stripe Tanning, come one come all...
;)
I wonder if those still learning the basics of how switch-mode converters work might find it easier to understand what the inductor is doing if it was explained in terms of current rather than voltage?
The current in the inductor cannot simply stop when the MOSFET switches off - the energy in the magnetic field continues to drive it in the same direction - it is this that produces the rise in voltage.
Self-inductance is analogous to momentum if you like to think of electricity in terms of water flowing in pipes where voltage becomes pressure, current is litres per second and capacitors are tanks.
I have some ASE3WE17 I bought back in early 2020 to make a UVC box, even got the AC power supply but just never got around to making the box. Found out the UVC can age plastics really quickly so didn't wanna risk my phone falling apart, even if it was germ free.
Could fix this design, and improve on the Schottky diode current problem, by just putting a second diode across that link. They won't be perfectly matched, but the safety factor will be back, and you'll have better current handling. Personally, I'd want to build an H-bridge driver for that lamp. It annoys my OCD that only half the filament is lighting up. 😅🤪😵💫👍
Very interesting tear down sir! Do you suppose it's worth it in the end?
If you have a need for low level UVC sterilisation it might work.
I think it is a weird as that the FU link is a way to makeup the voltage drop of the diode for MCU , cut the trace and see if it still works
If the link was not there, both the Vin and Vout pins of the chip would be one schottky diode drop above the +V rail of the rest of the circuit. In other words, at the same potential.
I think the circuit "designer" painted themself into a corner and couldn't think of any other way out.
can we expect shorter bulb life on dc? few years ago i tried a 555 at 12v/1khz big cap in series to give some fake ac but never got it to work. was trying to put it in a 12v fridge
I'm just surprised it was an actual germicidal lamp and not a fake like so many were during the pandemic.
Intriguing indeed. Possibly an error in the pic-n-place instructions.
WHAT if you remove the FU link? Then would it charge properly/operate properly?
Your best bet would be to replace that FU Link and the current diode with a better rated diode.
Perhaps the diode would be over driven.
Or, remove the link and first see if the existing diode can cope. The rapid escape of Chinesium smoke will tell us.
@@albanana683 The link is still redundant, since that's what diodes which get too hot generally turn into. At currents like here you won't even see smoke, it's not that much current.
Thank you!
Welcome to big Clive strip club, no stuffing around, straight to the tear down
You had me at hideous nevermind the fu link 😂
To me it feels like the designer of the board only intended for the 'FU' link to be populated if neither of the diodes were populated... but their intentions got lost somewhere on the way to production.
Coming soon... a library to include "FU Link" support for your favorite PCB-CAD software!
I need to look again. But I think the UVC bulb looks like the one in the desinfector chamber of a Philips toothbrush.
I was expecting the test card to confirm the UVC.
Have you put them somewhere safe?
You know: "I'll put them somewhere safe so I know where they are the next time I want to use them".
I have a UvC shoe sterilizer from Amazon that uses that same bulb. Only problem with it is the bulbs seem to rattle loose easily. Idk if it has the FU resistor though
Ah yes, the Fork Up link, always handy for reminding people that accountants got involved... :P
One of my favorites. Video that is!❤
I don't understand the F-Link but the way they designed the circuit board reminds me of being in my late 20s in 1986 and getting to use circuit board layout on CAD. I used to do some layouts with black tracer tape on clear acetate film 2x to be reduced by the board manufacturers years before at another company. The program was called P-Cad and we had a new 386 computer with a huge 40MB hard drive! Nowdays people can't believe it. Autorouting was fascinating to watch on the 14" CRT monitor too! Shit, I am not THAT old...
Yes, you are. But hey, at least it was not a 8086..
If they were concerned about voltage drop I wonder if they could have used a mosfet set up to be on with a grounded gate and pulled the gate down to ground with a resistor and then connected it to the positive USB rail
That’s nuts!
Thanks.
My question is...What would be the "proper circuit" to drive that lamp? You mentioned a royer oscillator?
Did you think of taking out the FU link and see if it would work ok? And also wanted say love all ya video's 💯% I like reverse engineering but never thought of putting all the work in that you do.. all I can say is just Thanks
All of my UV-C bulbs make a smell after running but they don't smell like ozone to me. It's more of a burnt smell and I can't decide what it is. My "reference" for what ozone smells like is a discharge from a crt flyback transformer. I've also worked with higher current discharges that are capable of making NO so I know what that smells like as well. Any ideas on what's going on?
Hmm, now you have me wondering. I thought the ionized air around a TV flyback transformer had a slightly sweet smell, while the ozone generator in the records room where I used to work had a similar but more acrid smell. I’m not sure which, if either, was more purely ozone.
Well hopefully it's not your flesh emitting the burned smell.
@@SianaGearz Indeed, in my experience UVC lamps make skin smell a bit burnt. The ionizing radiation breaks down molecules on the surface and accelerates oxidation.
How long would it take before you would have to worry about skin cancer or eye damage?
UVC is such a short wavelength that it doesn't penetrate deep into the dermal layer. It will cause skin irritation with time, but is much more likely to cause temporary eye surface discomfort in the same way that arc welding exposure does. The discomfort usually happens at night as a temporary sensation of having sand in your eyes.
Chinese Manager: Copy this thing!
Chinese Minion: YES SIR!!
It says 0R on the silkscreen so better put that one in without thinking too much
Maybe that is the option for an external 4,2v charger or something
This is why I never leave anything on charge. I charge things for about an hour and then unplug them. You just never know what atrocities are inside.
I can't help but wonder how the bulb would behave given the recommended 10V AC 3W vs this circuit.
What's the measurements or model of those lithium cells? My video camera has two parallel NCR 14400 cells that are dead
That could be a GaN transistor for better efficiency to make up for the FU link
Very strange arrangement
I often see instructions saying not to handle quartz envelope lamps, as natural oils on the hand will damage them somehow. Is this just BS?
In the case of these lamps it's recommended to clean them after handling to avoid oils blocking the UVC. For quartz halogen lamps it's to avoid oils that will devitrify the quartz at the high temperatures save cause it to fail.
I recall the same instruction. If I recall it was intended for bulbs that burned very hot and any contaminants on the glass surface might cause the glass to shatter. I recall the same instructions were given for halogen lamps, slide and movie projector (remember them?), etc...
Yes, the extinction path length of the skin oils for UVC is very short. It means a lot of the UVC is absorbed by surface contaminants!
The FU link… that’s for “Feature Unusual”?
Its a UV grenade for hunting vampires?
Why didn't you shine it on your UV paper to show if it is really UVC? wanted to see that
A mosfet could probably have done the FU-link job in a controlled way.
What do the designers know? That diode was clearly just unnecessary fluff!
(I'm obviously joking since they spent more on the wasted charge controller than the diode.)
And why would they leave in the charging circuit when it's bypassed? Only to use it as a charge indicator?
I would pay subscription for you to chat to the folks who built these things. Even though I can still only understand only half of it.
Ah, the FU link lol.
Maybe they were having a problem wanted to double down on charging all of the cells.
the phoebus cartel is a hot topic ...
Could you please test it without the fu resistor? There must be a reason why they did that
Good video 😊
Little brother robot entering the house. "Wow. What's that bright purple light lighting up Grandpa's window?" Big sister robot "It's his new tanning lamp."
\ /
#:-) &:-) ---- 8o] ----
/ \
My work phone (cubot j3 ) keeps puffing batteries. So as it lives in the car during use. I was thinking replacing the battery with a USB lead adding a resistor to the t terminal and maybe putting a diode on the 5v to drop it a little bit.
Plan b is attach a 18650 battery holder to the case and connect that in with a t resistor .
Either way it's my fu link to avoid buying another pillow battery and not make the cracked screen any worse. (I'm avoiding changing the phone as the work software is older version that does not autoupdate , I have the apk file but it doesn't pass on other phone)
It may need a battery to provide the peaks of current during use. Does it get very hot in the car? That might be damaging the battery.
@@bigclivedotcomphone does get hot I protect it from sunlight, the software is tough on the phone . Some days moreso than others , I think it's when customers check location it increases communication. GPS and wifi (no sim)
I have a 10A 5v supply, (12v input chunk of metal size of pack of cigs )runs dashcam relentlessly.
Not sure of sensible way to loose 0.8v or if it's even something I should be concerned about.
So for once they did give an F but still screwed up.
And this is why we should always check the charging circuit whenever we buy any cheap rechargeable devices from China.
Thanks Clive. This video helped us out a great deal working toward an off-grid UVC water sterilizer. Cheers!
What was its purpose?
I learned the hard way not to look at germicidal uv lights...
wouldn't the uv slowly make the plastic brittle?
In very long term use, yes.
Misread title, thought it was a genocidal lamp
Interesting that one may need a UV light that is portable
So, if you whip out that link, it'll operate correctly?
The charge circuitry will, but the diode may get stressed during lamp operation.
@@bigclivedotcom ...thereby momentarily increasing UV output (with the possible extra bonus of magic smoke!)
Are you supposed to touch those bulbs, halogen not to touch, Wright? Wondering if they are both quartz
Pretty sure the UV-C bulbs don’t get hot the way halogen does.
@@SkigBiggler oh, so it's the heat that causes the reaction. Thanks for the reply!
Birth quartz, but the extreme heat of the halogen causes issues with finger oils causing devitrification of the quartz. With UVC, finger oils may partially block output.
@@bigclivedotcom cool, thanks for the reply!
I don't own a single screwdriver with that funny looking insulation on it. I wonder if it's a European standard, because I first saw them on channels like yours or Techmoan's.
What is the purpose of the insulation? If it's a good enough reason, I would consider retrofitting my existing drivers.
Look up VDE screwdrivers.
@@bigclivedotcom Ahhh thanks, that's what I needed. So it seems there's more to them than just the rubber coating.
Maybe I should get a set, for when I'm working on high voltage tube based equipment.