DANGEROUS Chinese USB charger (no isolation in the transformer!)
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- เผยแพร่เมื่อ 22 ม.ค. 2018
- Today I made a teardown of a USB charger donated by one of my viewers and I reverse engineered its schematic. Then I found that the transformer in it has no isolation between the windings! This USB charger from China (fake Apple iPhone charger) has a transformer with no insulation tape between the primary and secondary side. The output of it (and thus the entire phone including its metal casing) is isolated from mains just by a super thin layer of enamel (lacquer) on the magnet wire! This means a very high risk of an electric shock and death. This dangerous electrocution device comes in various colors including white, which looks just like a real Apple iPhone charger.
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Your English is very good but your accent is crazy, it's quite addictive to listen to. :-)
I am the same nationality as him, but i must say, that his accent kills my ears. English is not my native language, but this still sounds awful even to me, like gearbox grinding, fakin pain in ears...
that is because he is indian from India and he's trying to speak english the same way he speaks his matern language. But i undesrstand almost all.
I think he's czech (according to other posts), it doesn't sound like the Indians I've heard and I've heard alot of them, lived along side of them for years, I've never heard anything like this guy. I'd like to hear him speak his own language, that would be interesting, only slightly mind you.
orange11squares he is definitely Czech
I thought he was indian at first but noticed he didn't quite seem 100% indian. Then I noticed Czech writing ... :P
11:57 The moment that DiodeGoneWild realizes that the auxiliary winding is wrapped over the top of the secondary, and that there is no mains isolation in the transformer...
Bloody hell
That's dodgyyyyyyy.
I love watching you dissect electronics. You're awesome!
Damn, this thing makes me feel much more safe using power supplies that I've made myself :D
cccp3 Exactly.
MrJohhhnnnyyy We've seen your videos MrJohhhnnnyyy... Your stuff is overengineered if anything, I don't think you've anything to worry about :-)
As long as you don't make capacitive droppers you're ok.
Now I am scared too, can you build one for me? Thanks
Your explanations are very interesting, both from a security and technical point of view. Thank you very much .
Your videos are always super informative, I always waiting for your videos... Thank you
Now lets go one worse and make a capacitive dropper based USB power supply! :D
Capacitive dropper will be luxury model, standard model will use resistiv dropper ! :D
Hi DGW! thanks a lot for your videos, they are very informative. your English is good I can understand every word you speak, and is also a melody and a background music which keeps me entertained. so thank you twice!
Excellent work and brilliant explanation. Thanks.
very good video, I almost saw all your video in this channel, danyk ;)
Would be nice if you will make more video about teardown of power supply or usb charger etc, and if you would give more detail about how it works, like how much current,voltage in which components.
congratulations for this cool channel !!!
Great video. This is a very interesting teardown of these Chinese deadly power supply. Thanks a lot.
Thanks for this video. I very much like your channel, accent and all! I second the motion of you adding a short talk in your language (chech I believe). Very interesting accent.
That's what I like: how things works, explained till the very basics. I've learned more from your videos than the read books or google results. A huge thanks man for your work, I really appreciate it.
Thanks :) I will do my best to keep making such videos ;)
I wanted you to do a video on this charger and boom new video posted ! Thank you 😊
Thanks a lot.
I always gain alot from your videos. Am from Nigeria.
Love the accent and dialect. The explaination and analysis is awesome.
Recently i went through the process of making my very own step down transformer (120VAC to 24VAC) from scrap (mostly for learning purposes, also because i needed a step down transformer for a variable bench PSU project), i reused the copper wire from a different (damaged) transformer and wrapped it around a toroid... The process of isolating the iron core, winding the primary (750 turns), isolating the primary and then winding the secondary (90 turns) and then isolating it took me in total some 12 hours. And it worked! i plugged it into mains (keeping some safe distance just in case) and it started humming and giving almost the correct voltage on the output... 25 seconds later i realized there was some magic smoke coming out of it...
The diagnosis is that i didn't use any kind of hard resin to hold the sheets of the core tougher OR the windings in place (usually the same resine they use to work with fiber glass is used) so the transformer worked fine but it vibrated itself into almost a meltdown in just a few seconds.
The one thing i learned very quickly with the experience is that transformers are simple but annoying to make, and that there are many things that can go wrong with them in a quite catastrophic way and they usually involve cutting corners or saving on materials like i did, or like the chinese did with those transformers with no isolation between primary and secondary, those tiny things are nothing short of a fire hazard.
Ended up scavenging a transformer from a damaged PSU for my project, works perfectly fine and i can use it as a step up transformer as well.
Wow. That's incredible. I'm glad that it failed while you were monitoring it and not some time later.
I like all your videos. They are really eye-opening.
I subscribed to you because your accent is quite enjoyable to listen to and your videos are great
Perfektní video, moc děkuji.
are you mehdi's (electroboom) long lost brother?
I had one of those when visiting Romania, it blew up while we were out enjoying the trip. It had literally blown the caps into pieces.
i think i learned more from this than from any electronics video i've ever seen.
Very Nice Video! Greetings from Poland!
After a fake Apple charger emitted black smoke while charging my iphone I made up my mind to never use anything, but a real Apple charger. Thanks for making this video demonstrating how dangerous these cheap chargers can be. The ipad rehab youtube channel also demonstrated the difference between a genuine Apple charging cable and the cheap aftermarket ones and again my phone will only be using an oem cord or an Apple approved one. Phones are too expensive for me to gamble on a cheap charger or cord. I thoroughly enjoy your channel and content. Take care!
I think that most of the chargers bought in supermarkets are kind of OK and approved / tested for safety. For about 4 - 5 USD you get a good 1A or even 2A charger. But if you buy something from ebay for 0.80 USD including shipping, it just can't be good.
DiodeGoneWild Yeah there's a big difference between aftermarket and fake... Plenty of good usb chargers on the market these days for much less money than Apple or Samsung charge.
I don't trust the USD0.80 charger , they are good for people who want to remove and modify something. The USD0.80 is good for buy a casing with a starting component there, need some skills to modify before it can be use.
@@DiodeGoneWild Here in Indonesia, reputable online electronics shops sell a 5V 1A charger for $0.42 (6,000 IDR) with the warning "Application: Can be used on Mini USB Fans, Color USB LED Lights, Toothbrush LED Lights, etc. & Not for Mobile Equipment" but I bet that it's the same as shady people sell for much more because it has all the Samsung markings. I bought one just for fun to test and take apart but I haven't yet.
Ikea makes high-quality and safe chargers. Good alternative to the "official" ones.
Great video. There are many dangerous discount electronics on the market today.
i subcribed i liked your videos interesting seems your master in this field. and i like the way you talked 😁
Thanks for vid! Huh, what a dangerous device!
very informative and clear. now i saw the difference.
Sir thank you for the very educational video. I always love seeing video of smps reverse engineering and your are the most informative and detailed on the internet because you give a schematic and of course you take apart the ferrite and count the winding turns. However i want to add on the leathal and dangerous smps you reviewed that i thin it is not current limiting to 0.6A, i think that it just this is the max current it can give according to its poor design and performance. In detail the current limit using SS8050 epitaxial npn and 10ohn base resistor to ground can be calculated. Its base emmiter On voltage is 1V but i think it typically starts to conduct on 0.8V V(base-emmiter). But 10ohm sense needs 0,08A according to ohm's low to reach 0.8V (max allowed primary current) so the primary current is design to be limited to 80ma. But primary turns is 175 and secondary is 12 so that gives us a Turns ratio of about 14.5. In smps transformers the ampere-turns ratio gives us a peak ''reflected'' secondary current (n=14.5 Ipr=0.08) of Isec-max= 0.08X14.5=1.16A which isclose to rated 1A so i think that they somewhat used the correct math and equations for the current limit part, but unfortunately the rest of the design is so bad an transformer so small (and maby low frequency) that it just cannot output 1A thus it will never be able to reach the secondary current limit threshold!
However because of bad design maby it reaches current limit because of transformer inductance touching saturation limits so it peaks primary current and triggers current limits due to fall of magnetic flux that normally holds primary peaks and not because of the secondary to primary normally reflected current load.
Thank you and goodbye! Keep giving us so educational videos! its just like watching discovery channel for me!
This is the most crazy power supply I've ever seen.
hello forgive my ignorance ... noticing the scheme that you made this circuit without the bridge of diodes but only one in the negative pole can you explain from where it guarantees a continuous current at the ends of two or three transistors? THANKS ....
You are very smart. Good job.
love your videos
At 1:55, looking at the silkscreen, it looks like the primary switching transistor Q1 was supposed to be a TO-251 or TO-220 package, but someone decided to just stuff in a TO-92 instead. Must have gotten a good deal on a pallet-load of TO-92 transistors at the Shenzhen market. Just use a higher value current sense resistor and it'll be fine...
I just bought two slightly different versions of this charger on eBay. I have to see this horror show for myself!
Great video -- thanks!
Yes, it was probably designed for TO-126 (for example 13003) or TO-251. But they put a 13001 in TO-92 into it to save costs. It kept overheating, so they reduced the current limit.
Excellent vid demonstrating you do not always get what you think
Very dangerous... Thanks for this Video
"Praiiimaree whydeen" yeah it's addictive jeje.
Very Nice video i would never buy a cheap chinese usb Charger. Thank you for the good information
So the only isolation is the lacquer coating on the wire. If that's the build quality of the transformer, you have to wonder about the quality of the lacquering as well!
Funny pink death adapter :)
Funny until you get the shock :)
Yes^^ It's crazy what some Chinese factory design and build!
ZK-999 th-cam.com/video/ioAq7PI1Uwg/w-d-xo.html
Do you have a book explaining these smps from begining and how to repair them ?
The flyback is self excited RCC converter , They usually use MJE13001 as main switches which have only 400V of Vceo , When your input to main is 230VAC after rectifier will be 320VDC , In order to make flyback work they are transfer energy during turn off, By looking the winding , assume secondary output 5.2V (0.2V drop by 1N5819) with 12 turn and primary having 175turn so primary will reflect 75.8V , and this voltage will add with 320V which is 395.8V and appear in Vce during MJE13001 turn off which very close to 400V , if your input voltage is 250VAC then it will exceed the maximum of 400V. during turn on , 320V will go into primary of 175 turn and secondary 12turn will appear 21.9V which is still good for 1N5819 which is maximum of 40V .
For the non isolation of Aux winding is crazy.. i believe they are copy from someone product without understanding. The ceramic cap as Y cap is so dangerous , ceramic cap are easier to short circuit during failure.
I love the accent! This is damn scary! I tell my wife "No Gas Station Chargers! I don''t want our house to burn!"
did you had a fujifilm charger bc-45w diagram.. were i can input 5v power coming from Power Bank
The Chinese designers should take some safety engineering lessons from you. It is dangerooous to say the least. Keep up the good work, Prof.
They don't care about safety, all they want is money 💰
Why do they even bother with the capacitor between primary and secondary? Isn't it only for EMI filtering?
very good ...thank you.
The position of the rectifier does not make the input circuit a voltage doubler. Your analysis would be equally correct in the case of the diode being connected at the other side of the line supply. In any case this voltage doubling has only to do with the maximum peak inverse voltage (PIV) the diode can withstand. During the second half wave this diode isolates the circuit and therefore is exposed to double voltage. The circuit (load) will always see the peak line voltage as a maximum, minus that diode forward voltage drop. On the other hand the filter capacitor voltage rating is 400V. As for all the rest, this is a good job.
can you review the Huaweii and USB Power Adapter of Apple please
Your accent is CRAZY!! :D
Thanks for the videos focusing on power supply construction and functionality. People should spend good money on a quality product rather than spending cheap on a product that can ruin your life completely.
It looks like the transformer and the output transistor are the bottle neck of the circuit. Would it be possible to just gang up 4 of these power supplys and put the output in parrellal to get the specified 1 amp?
why did you not measure the isolation resistance between the primary and the secondary coils with a megohm meter before unwinding all ?
23:32 That's probably double-shot molding. i.e. the darker plastic is molded first then inserted into the mold for the lighter plastic. You see this used for the lettering in high-quality keyboards as well.
One of these made loud noise when I put it into 220V plug in a train. They are also offered by china seller at flea markets.
It looks like the solder is pretty thick. That, along with the leads not chopped very close to the surface of the solder, leads me to wonder if it wasn't put together by hand!
Same here
Just checked some 5V 1A chargers of the same style my father bought in packs of 3 from german (!) Ebay stock.
The components seem to be higher quality (full bride rectifier,...) but the transformer still has the same shocking construction .
DeadFishDevelopment full *bridge* rectifier
I like my wives to be positive, no matter the polarity of the input
Hello, nice film! But From where you have 340V? Its 240v iven if its doubled it isn't abot 680but 480v. But rest of video its ok. BR
@@keysejkeysej 240V is effective voltage, max voltage on AC is +/- effective voltage * (square root of 2)
@@300maze hi, yes Maybe you're right. In peak you have 679V ,but effictively still 480V. BR
When you say ‘isolation’ is this the same as ‘insulation’? And therefore, what is meant by a safety isolation or isolating transformer? Thanks,
Pretty much. A transformer is usually a pair of coils wrapped around a metallic core. Ideally there is no path for current to flow from the primary coil (i.e the side connected to mains) to the secondary coil (the coil connected to the USB port). Since high voltage can jump across lines if they are packed tightly together, you need more insulation in the form of physical separation of the mains and low voltage sides. This is *isolation*
Where did you get that exacto knife from?
Thank you
Can you open an Sonoff Basic to see how is the power supply in it.
At 9:28 it's 0.6A on the primary side, but it can be much more on the secondary because of the transformer ratio of around 1:30.
Otherwise Thx for your explanations on that death trap.
The second one has a big flaw concerning the emi capacitor: due to its position, its cold side lead is very close to the hot side of the optoisolator.
But you didn't notice the complete lack of any isolation in the transformer? :)
I have warned people here in Finland about these one euro chargers. Thanks for opening the real Apple charger so I don’t have to. =) If you weigh those, there is a huge difference between fake Chinese and genuine Chinese Apple chargers. Also the real one has a serial number in the USB connector which you can see on this video. BTW, I like your English. I know that you are from Czech Republic but your pronunciation sounds like Indian accent. Well, the most important is that you speak clearly. I was once in a Sony Betacam maintenence course in England and there was a Czech guy too. He had huge homesickness but was nice and kind person. I’d like to find his email address as I have some photos. I didn’t find anything when googling his name.
Please does testing device where can I get them. I need them very important to me thank you for your response
This is the charger that killed a young Chinese mother of two who was studying in Sydney. This is absolutely criminal.
love the way you pronounce 2 and transformer
After I started watching your channel I instantly took apart my phone chargers to take a closer look.
Few years ago I destroyed a Raspberry Pi and 2 HDMI outputs of my TV with a cheap chinese charger which had mains on ground. I was lucky to didn't touch the shielding while plugging it in.
Isn't there a cheap and affective way to test chargers from the electrical side to sort them out?
Reputable shop/brand + above average price.
I'm tempted to buy two. One to use and one to take apart but then I just buy a better one for twice the price (but lose the learning.) I do test the voltage under load to ensure that it's reasonable. I don't want to take apart the ones that I want to use because I don't want to be the one to inadvertently mess up and make it unsafe, even if the risk is low.
Output volt only 2.5 volt got. How can solve this problem to get 5 volt output. Pls reply
Sir, how dose work axillary wending in SMP transformer
Its called positive feedback
So the secondary winding is in contact with the auxiliary winding, and the isolation on the primary winding doesn't go all the way to the edge, meaning that some of the primary is touching the secondary and auxiliary widings, and as such all 3 windings are just isolated from each other by the lacquer on the wires, which is 0.005 - 0.05mm thick. That's super dodgy!
Absolutely craizeeeee
Please make a video on how to reverse engineer any circuit
I have a charger that i want you to take a look at .where can i send it?
When winding motors maximum voltage diference allowed betven two touching wires is 100 v.But this varnish in these wires is way thinner.
You're right. And on the top of it, if the insulation breaks down in the motor, it only makes the motor fail. If the insulation breaks down in this charger, it will electrocute somebody.
Ahoj tvoje čecho angličtina je super :D
oh, i had one of those. It exploded and blew the 16amp fuse.
I have two of them payed 1$.
I don't use them in my cellphone because i know they are dangerous.
So i bought them on purpose
The best thing about that transformer was at 15:45 when the cat decided to play with it, as a cat toy :)
As for it being an actual functional transformer...
12:01 "Well... wait?! I can see wires coming from both sides of it!"
12:34 "So is there really absolutely no isolation between... just the layer of varnish or lacquer... that's just absolutely crazy!"
Yeah, seems safe enough to me. ;)
I just want to hear you say "dangerooos" over and over!
sir..if i remove the zener diode what will happen with the output voltage? thanx
Zener diodes typically are used to limit the voltage output. I'd expect it to go very high until a load is added
A Y2 capcitor would be sufficient. I think the test voltage would be 5kV (according to the norm for double insulated equipment).
Y2 should be rated at least 2kv dc
What is the function of the optocoupler in smps?
Its like some sort of isolator, one part uses an LED that makes light and passes to a transistor, check how optocouplers work
I have yet to see a PS failure due to an insufficient primary/secondary winding isolation gap. I don't doubt it happens. I would just like to see an example of it
Looking at listings on Amazon and eBay brought me here. Why do these sites allow cheap electronics to be sold? It’s even more jaw dropping when you see the exact same product but with different brand names. Rumour has it a generic product is produced in the same factory and then you can add any label to the casing afterwards
Time to bring out the variac and microwave oven transformer for some primary to secondary Hi-pot testing.
My guess it will survive at 800 VAC for 5 seconds but fail 2kVAC within 30 seconds
You should look at Testing Poundland's 2.1A dual port USB power supply. (with 2kV) th-cam.com/video/aS1pwoVdRh4/w-d-xo.html
Could you wrote the wires thickness
Thanks
+DiodeGoneWild
well, not all wire lacker is designed for low voltages, accualy most such wires can handle up to 300V betven them even if they are touching, and I even tested such two wires (which I unwound from a normal step-down mains transformer) with high voltage, and it surprisingly handeled 3450V~ before it broke!!
but this comment doesn't mean that all wires can handle 300V (or even 3500V!), some of them realy are made cheaply and can handle only about 100V, and that's not even considering the fact that there may be some cracks in it and the lacker may be damaged or even completly scraped off in some places!
what part gets hot when charging ??
The written current rating is propably short circuit current.
That's criminal. Do we know how they're able to get away with using the logos for the various safety/quality agencies on the case (I saw at least "CE")?
I reply VERY late, but that CE branding is counterfeit
You are the best.....thx
oh wow No isolation tape between the windings? they are getting cheaper and more dangerous! Back in the 50's and 60's transformers had high temperature insulation. The laquer based wire coating could withstand 500 to 700 degrees. Todays commercial insulation is designed to melt off with a soldering iron for much faster production and assembly.. eliminating the need for magnet wire strippers, but making for very unreliable, early failing devices. as these windings cant stand even 250 degrees F for any length of time!
Teardown some original charger
I had the same charger, it EXPLODED after 10 minutes of use! I even have a video about it in my channel :D
cool video! :)
Ive seen one of these go bang and now I know why!
I was half expecting a capacitor dropper.
9:09 Pokud jsem dobře porozuměl pasáži o max. výstupním proudu, že to není 1A 5V ale méně, protože snímací rezistor na primáru to omezuje na půl ampéru. Ale to omezení platí jen pro proud primáru.
This is the kind of charger Clive rapped about!
Very good .......
Qual o nome desse medidor, multímetro