USB power supply puts 220 Mains power out on USB jack
youtube.com
youtube.com
E.g. Compare Big Clive's mention of a full bridge rectifier in the video vs Mehdi's YouTube video of the same thing :)
However, on the serious side, I wish that he would publish a complementary video showing the real story of what he is doing.
My kids would watch his videos, and then run off the find the bits to do exactly what he did. Hmm..Luckily I was there to let them know of the real consequences.
It hurt A LOT. Granted, my hand was wet a little, but man it fucking hurt.
The only reason that didn't set the building on fire was that I was right next to the speaker when it burst into flames. My immediate reaction was to assume my SO playing a really unfortunate firecracker prank on me, but half a second later it was obvious it was the speaker's fault. Turns out batteries can make pretty flames and a lot of fairly unpleasant smoke. To this day, still can't believe how lucky I was to be right next to it with a pillow as it blew up.
The company was kind enough to send us their top of the line product for the incident, in exchange for the faulty unit (for them to study) and a written agreement to not take em to court.
Still pretty uncomfortable around charging devices with batteries to this day, but the reality is that it's unavoidable and there's no point in developing a phobia about it.
For them to study, or for them to destroy the evidence so that you absolutely could not take them to court.
Did he miss an opportunity or an opportunity cost?
And yes I would imagine that there could have been some cost associated with cleaning up the smoke smell left in the room and possibly any burned areas.
The transformers made 80 years ago were indeed dangerous. Generally they used paper insulation soaked in fire retardant chemicals.
There are a couple of observations I make about this video:
1. She's working amazingly fast and clearly with great skill. However, there's very very little time being spent inspecting the result at each stage.
2. Observe that she is holding sharp wire cutting scissors in her hand as she performs many operations on the insulating tape and wire. It would be extremely easy to accidentally nick the insulation when working at that speed. This insulation is the only barrier between your charging iPhone and the 120/240 mains voltage (or higher in a switching supply).
3. This transformer design is not the safer more modern "split bobbin" type as suggested in the original video. Instead of having a plastic barrier between two separate windings, it relies entirely on the enamel insulation of the transformer wire and a few layers of insulating tape between concentric windings. The precise number of insulating tape layers is essential to achieve the necessary safety insulation. The white tape wound along the sides is important too. Watch the video again closely. How careful is she being to count the number of layers of insulating tape? It's possible her winding machine is counting them, but this step flies by so quickly it's a bit worrying. Edit: This may be extrapolating a bit because it may be we're seeing the outer, rather than an interposing, layer of tape being wrapped in the video.
4. The transformers are piled haphazardly as they are being constructed. They are heavy and the bottom pins can have get a pretty sharp point on them. I bet some of those transformers at the bottom of those piles are getting their insulation punctured.
It's amazing though! Working that fast.
It's also just what the client ordered, if they wanted better quality they'd have to pay for it.
There's surprising amounts of skill in these unskilled / semi-skilled jobs.
If you're sitting at a machine winding transformers for 8 hours a day, and paid for each item you make (and fined for each item that fails test) you quickly get faster at winding transformers.
>Why do you think it's sped up?
One of the many reasons I detest "double insulated" equipment, as it is impossible to determine if it has been designed for safety or not without ripping it apart and destroying it.
This is a real issue in Australia as our regulators do no regulating and most equipment I have investigated does not comply with Australian Standards even though manufacturers lie and put standards compliance numbers on them.
Also the Australian Standards should be considered an absolute Minimum not "super safe".
The CE marking in Europe is the same (in most cases). It just means that the manufacturer declares it is compliant, not that it has been approved and tested by anyone.
If you are into more... entertaining teardowns you should have a look at AvE. Even if you don't like it you will still learn some useful canadian terms ;) (edit: just to make it clear, AvE is actually very knowledgable. His "boltr" teardown series of electronic power tools is most likely the most thorough you will find on the internet)
My third goto channel for electronic stuff is EEVBlog who also does amazing stuff. If you are going to watch one teardown today then please watch his rather famous video about the worlds worst tablet computer: https://www.youtube.com/watch?v=2o8MDCIlOEk
His style is... unique. I think it's great but I'm sure it's not for everyone.
I'm crying out of laughter right now. This is absolutely brilliant. That is, the teardown - the tablet itself is an abomination. Thanks for posting this. This channel is great and seems to have a lot of educational content besides teardowns too.
Yes, but I find myself strangely impressed. I like to imagine someone walked up to an engineer and said "So, I just told client $foo that we can provide a tablet version of our PC software. They need it by end of week. That's not a problem, right? Because the CEO is fully on board with this..."
It just seems this guy expects everything to look like an Apple ipad when you open it up.
Oh boy, that thing is a MESS. When he first opened it, I thought it looks like the sort of thing I'd knock together - not pretty, probably mildly unstable, but gets the job done. Then he took a closer look, and it's the sort of thing that wouldn't even be acceptable as a secondary school project, never mind a device to be sold.
https://www.youtube.com/watch?v=5i7_-NtJeB4
Someone has to review them...
Much better made.
Some of them are incredibly obscure such as the Tefifon: https://www.youtube.com/watch?v=nBNTAmLRmUg
> My third goto channel for electronic stuff is EEVBlog who also does amazing stuff. If you are going to watch one teardown today then please watch his rather famous video about the worlds worst tablet computer: https://www.youtube.com/watch?v=2o8MDCIlOEk
If this is not enough then go and visit this list:
https://www.reddit.com/r/ArtisanVideos/comments/3v264a/meta_...
(But be careful, this is the ultimate rabbit hole)
As a side note, I'm starting a blog where I interview heavy equipment operators and write about heavy equipment. Anyone here interested in that?
Um, I mean, yes. Yes, I am interested.
Over on Amazon, anyone can offer something for sale. And the only real indication you have is the "sold by XYZ, fulfilled by Amazon" line somewhere near the top.
The site is amazon.com, the logo and design is all Amazon, but Amazon never had to place an order for the item, nor is on the hook if something blows up. They just act as a combo of UPS and Paypal for the transaction.
The practice is called white labeling: http://www.investopedia.com/terms/w/white-label-product.asp
Basically an Amazon seller sources product from China and gets the manufacturer to label the product with their brand name. Quality can be either really good or dodgy.
However, I have seen a lot of this stuff with the CE mark but not the UL mark.
Do the CE underwriters just let anyone stamp their mark on any product with minimal oversight?
The manufacturer/importer is supposed to be able to produce evidence of compliance on demand, but if it's posted from China, good luck with that. This is why the products are so cheap.
I think for Anker, their brand has become a bit bigger than is gamble-able on a bait and switch, so I'm continuing to use their products.
Instead of trusting a particular brand, I think it makes more sense to trust the various security certifications that were created for this purpose.
The ones I am aware of are:
* TÜV Nord, TÜV Süd, TÜV Rheinland (TUV, Germany)
* GS (Geprüfte Sicherheit, Germany)
* UL (Underwriter Laboratories, US)
* CCC (China Compulsory Certification, China)
There are probably more that are trustworthy and that actually check the safety of the devices.
No, somehow we have to charge all those batteries ;) A lot of people use Anker products for this as well.
Supposedly the CE marking in Europe should be a good indicator, but sadly there are various ways that a company can self-certify products.
I think the biggest problem is that Amazon allows anyone and anything to use them as an outlet by default. Thus many fly by night resellers can used Amazon's brand as a cover.
The manufacturer/importer is supposed to keep and present on demand a "technical file" detailing compliance to various standards, which is supposed to include particular tests, but there's no real guarantee that they've been done.
On the other hand, this is a major barrier to entry to small-run products, as is WEEE.
Suppliers register and prove that their products comply with Australian standards, and are awarded a compliance number. That number is the consumer's indicator that a product is safe. Any interested party can check that the certification is genuine by looking up the compliance number in an online database.
Here's how it works in practise: you're screwed. The relevant government department took the database off line years ago, and there still isn't a replacement. When you go to do a search, you arrive at a page that talks about the database in the future tense [1]: "The national database will list all the equipment registered by the responsible supplier". A supplier can put a fake mark on a product, and there is no easy way for a consumer to know if is genuine, making the marks virtually useless. The result is electrocution whilst listening to a plugged in music player with headphones [2].
[1] http://www.erac.gov.au/index.php?option=com_content&view=art...
[2] http://www.smh.com.au/nsw/warning-over-usb-chargers-after-wo...
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Edit: spelling
I think I answered my own comment a few sections above. But for safety you should look for the UL mark:
http://www.ul.com/code-authorities/resources/faqs-for-code-a...
The CE mark is the manufacturer's self declaration of compliance with EU law, sometimes including safety.
Whereas the UL mark can only be put on products that Underwriters Laboratories have authorized themselves.
"The photo below shows the safety certifications that the charger claims to have. Again, it looks genuine, with no typos or ugly fonts."
Or http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pr...
"The counterfeit charger displays a bunch of certifications (such as UL) that it doesn't actually have. As you will see below, there is no way it could pass safety testing."
There's a lot to be said for split-bobbin transformers, where there's a solid plastic barrier between the two windings. This just has wire insulation and some tape.
He's reviewed numerous really questionable power supplies[1] with a gnat's whisker of separation between the mains and low voltage sides and much more dubious transformers, but somehow none of those actually managed to put 240 volts on the output...
[1] Such as the cheap shitty pink USB charger from China: https://www.youtube.com/watch?v=ioAq7PI1Uwg
That's the argument for a split bobbin. With a hard plastic wall between the two coils, in addition to the wire insulation, it's hard to get a short between both side of the transformer.
Here are some split-bobbin transformers for switching power supplies on Alibaba.[1] Split-bobbin seems to add about $0.10 to the price, raising it from $0.89 to $0.99.
[1] http://wholesaler.alibaba.com/product-detail/EE22-split-bobb...
So, there it is.
Good luck finding a miscreant to hold accountable if this sort of cost reduction kills someone. And even if you could hold the culprit accountable, that still can't undo the loss of life anyway.
It's all just collateral damage from the race to the bottom.
It's always about tradeoffs, sort of like how you can ride a motorcycle or drive an armoured vehicle. What is safer won't necessarily be better in the other dimensions.
I'd doubt that any significant amount of fires are caused by loss of isolation between line and output side. While it might be very unpleasant to touch any device that came into contact with the live wires, there's not really much current you can have flowing. And if any significant current flows, a GFI should catch this, and shut down the power.
Regarding the amont of deaths by electrocution: How much people are actually electrocuted by badly designed house appliances? As far as I see there's only very little injury related to electrical shock outside of actual electrical or construction work, where people might naturally be more easily exposed to live wiring carrying higher currents, possibly higher voltages and, most importantly much lighter standards in terms of circuit breakers.
Would love to know if the mentioned capacitor is indeed the reason and whether it leads to enough efficiency to justify the scare it causes with first time customers.
They are not expensive, but they are the best products you can get your hands on. I own multiple Anker products, and have never discovered anything better than these.
The only non-Anker charger I currently use is the Google Nexus branded Qi charger (plugged into an Anker multiport brick), and the original Chromecast brick plugged into my Chromecast.
I don't understand why this is so hard. My first smartphone, a Samsung Galaxy Nexus, came with one, but it failed within a year and Samsung wanted like $50 for a branded replacement.
On the flip side, Anker chargers speak both, and charge newer iPhones and iPads faster than that huge iPad charger does.
Also, their 5 and up port new and old ones don't hang off the plug, they have a short normal power cable.
https://www.anker.com/products/71AN3654WS-WA
This is the one I have. Their new version of the product doesn't seem to be oriented that way anymore. So, yeah. Not quite what you were looking for, but they do exist.
I probably will give them a go now, but they're in bad company.
Wall charger still works great, but the cables are what I was really interested in because people are always running off with them. Still haven't found anything satisfactory.
I just want cables without the hassle of going through warranty and RMA processes. It's possible I just got a bad batch - I can't believe people would be as positive about Anker if my experience was that common - but it did sour me on them. I just want to find a manufacturer where in my experience, the cables I buy are good 100% of the time and last for at least a year so I can buy them in bulk and recommend them to others with confidence. And I haven't found that.
But some of them have simply stopped working after use on my desk or being carried around in my backpack for a while. I've switched to aukey for cables for that reason. Whether they're any more reliable is TBD.
http://asndata.aviation-safety.net/reports/2013/20130712-0_B...
...caused by a battery short resulting from the two wires being trapped against the case and eventually the insulation abrading through when subject to vibration. Even the highly regulated aviation industry isn't immune to simple defects like these.
In order to do this it rectifies the mains input to high voltage DC (330/220Vish, depending on the mains voltage) then using a power transistor rapidly switches this on and off at around 1-10kHz. Then the transformer outputs low voltage AC which is re-rectified and filtered to produce low voltage DC.
The switch mode chip monitors the output voltage and modulates the switching frequency to maintain a constant output voltage.
If you look closely at the board (and he talks about this in the video) there's a separation between the high and low voltage sides. Only the transformer and certain specialized components should cross this (Y-class capacitor and optoisolators). Cheap power supplies often miss this out which could allow a small bit of loose solder being able to send mains voltage to the output. Look at other videos by Big Clive to see the horrors.
The high voltage side is a bit of a misnomer. It's really just the non-isolated side - the chip runs on 5v or similar, but it's not completely separated from the high voltage DC so isn't safe for human contact.
How does the chip get 5V, out of interest? Given that it's not allowed to be connected to the non-isolated side?
Switch mode transformers have three or four sets of windings. The primary (high voltage), secondary (low voltage) a bootstrap winding (for the chip) and sometimes a flyback winding.
The bootstrap winding takes off a variable voltage depending on the local supply and uses a linear regulator to produce the required voltage.
For a better explanation than I can manage in text the EEVBlog channel goes in to all sorts of regulators and how they work: https://www.youtube.com/watch?v=cM7t1Mpu7s4&list=PLn-ZIFhWxh...
Got a nasty bite as soon as I touched it.
Got what I paid for I guess. Made me rethink super-cheap AC equipment from the internet, that's for sure.
[1]: www.amazon.com/Kohree-Digital-Rework-Station-Solder/dp/B00ITMPQS2
I think EEVBlog highlighted this with the FTDI case. People were buying what they thought were authentic FTDI chips (and paying the proper price) but being delivered fakes that then went on to be bricked by the driver update.
There is so much margin in swapping good stuff with dreadfull stuff there are several points in the procurement chain where people can try their luck passing off crap.
Check out this video for a story of a risky thing he did with a heating element and a bath (4:30 is where it really gets going): https://www.youtube.com/watch?v=uUn17ccR2a4
why did the fault not stop after i pulled out the first two components? wouldn't that break off the power circuit inside?
why did the fault stop after he removed the transformer?
The fault probably stopped after he removed the transformer because in the process of desoldering and yanking it from the board, he caused enough strain/vibration that whichever wire was shorting the primary and secondary windings moved and was no longer causing a short. That sort of intermittent fault is common in hardware, and quite annoying to debug.