The larger Chinese-made chargers generally don't have these issues (though a few apparently do).
Notice that this fake contains all or nearly all the components required to build a safe and working charger, including full safety isolation, fuse protection, and output regulation. The manufacturer's entirely capable of building one, they've just fatally compromised on safety in order to fit everything inside a tiny fake Apple shell.
(The blog post says it doesn't have a fuse, but generally instead of having a seperate fuse the input resistor on these power supplies is a special fusible resistor which is manufactured to also work as a fuse. Saves a few cents and some space at the cost of using a specialist component. Unfortunately it's impossible to tell it apart from a normal resistor just by looking.)
Author here: it was a surprise to see this old article on HN. To reply to your comments, even if you fix the safety problems, this charger would generate really terrible power. They're using a primitive RCC circuit instead of spending a few cents on a controller IC, and they're using low-quality capacitors. I have oscilloscope traces at http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-ap... that show the huge quality difference between a $2 charger, a good charger, and an excellent charger.
I'm familiar with fusible resistors, and this charger doesn't have one. I've also torn apart the transformers from cheap chargers and the transformers are usually unsafe due to insufficient insulation.
These cheap chargers cut corners everywhere. You're likely to have touchscreen problems while using one due to the poor power quality.
I have an friend's fairly expensive espresso machine in pieces in my living room due to electrical "problems." The (indeterminate far east supplier) blatantly omitted about half the input side circuitry, including the supply filtering. Numerous components identified on the PCB were never installed.
One lonely resistor protected the IC V_in for far longer than I would have imagined possible (years) before exploding.
As someone who is actively working to increase my electrical circuit-related design chops, intuiting how this thing continued to operate has been an interesting exercise.
This article is old (March 2012) and has been submitted at least twice prior. Here's the small discussion from the last time this was submitted to HN, over a year ago.
I bought what looked like a legit iPhone charger in Turkey a few weeks ago. However, if you touched the tip of the cord while it was plugged in, it would shock the hell out of you. I guess they skimped on a ground wire? I am not an electrical engineer. Would appreciate an explanation if anyone can speculate.
EDIT: I don't use this charger anymore, just to be clear.
Chargers typically aren't grounded. The AC and output sides of the charger are electrically isolated, but it seems like that isolation isn't working in your case. It's not uncommon for enough high-frequency current to leak through to be felt, but based on the description it sounds like you've got full AC leaking through. I strongly recommend you don't use this charger, since there's a real risk of electrocution in that case. I wrote the original article, so if you send me this charger I'll tear it down, figure out what's wrong, and post a writeup (my email is on the article page).
Shocks "the hell" out of you sounds substandard, but even OEM chargers leak noticeable current. I'll get a bit of a tingle by being in the circuit of HTC Evo 4G charger - phone case - me - laptop case - T60 OEM CE charger running on 120V. And the reason I even have the grounded CE charger for the T60 is because I sent the US one to their engineering department for having way too much leakage.
I don't think the legit chargers _have_ a ground, at least around here they don't.
What it sounds like is that you have a direct connection to the mains, BUT EVEN IF YOU DON'T YOU SHOULD CEASE TO USE IT RIGHT AWAY. GETTING SHOCKED IS _NOT_ HEALTHY.
Possibly a transformerless design... regardless I would guess that the DC ground side is connected to AC neutral... (but only when it's plugged in the right way and when your outlet is wired properly), so plugging it in backwards connects DC ground (the exposed shield on a USB connector) to AC Line voltage. ZAP!
Hesitant with good cause, is it really worth the risk? Add up the time you're spending shopping around, reading reviews, the thousands of dollars in electronics you could burnt up, the pain of trying to use your warrantee when you violated it, and losing those files you forgot to back up; all to save what $20.
I have been using a 12v GPK charger for my MacAir for over a year. No problems at all. In fact it powers two MacAirs most of the time. (Switching the plug back and forth)
I'm guessing Amazon would be liable if they sold non-conforming devices, no? The charger described in the article clearly didn't respect the rules. Or maybe it's different in the US.
Amazon sells busted, bootleg products all the time, and the reviews can end up in the 1 star area. They don't pull them.
For a while literally all the XBox 360 wireless controller adapters on Amazon, for example, were Chinese knockoffs. For some reason Amazon stopped stocking the real ones, and let vendors put up knockoffs branded as the real thing, despite the reviews making it clear that they were fakes (and broke easily).
Amazon often has problems with listing knockoff products under the same SKU as the real thing. The Arduino project has had some serious problems with this in particular - for a while, if you bought an Arduino board, it was a roll of the dice whether you'd end up with a genuine one or a knockoff.
I bet the same thing was happening with the XBox controller adapters.
The charger I tore apart was from eBay; see the article for details. Cheap chargers shown on Amazon are typically sold by third-party sellers, which I think lets Amazon sidestep any quality issues.
You should. This was common with PSU supplies back in the 90s - there were those so called Chinese firecrackers that just blew up and had a concrete brick to give the feeling of weight inside.
Then the market matured a bit and now you have gems like Seasonic and a stable manufacturers like Fortron that in the 2003-5 were with extreme performance for their price.
Don't pay the apple, samsung, MS and whomever tax if you can avoid it. It is unhealthy for the market and for the wallet. Just do a simple research that you are getting a kosher device.
If you buy a charger for $2 on eBay and it's sent from China, it's almost guaranteed to be dangerous. If you buy a $19 charger from Apple, it's going to be as safe as you get. If you buy a cheaper charger from a store like Target, it'll be safe but probably worse power quality. More or less you get what you pay for. (No charger is 100% safe of course; Apple chargers have had recalls and occasional problems.)
Notice that this fake contains all or nearly all the components required to build a safe and working charger, including full safety isolation, fuse protection, and output regulation. The manufacturer's entirely capable of building one, they've just fatally compromised on safety in order to fit everything inside a tiny fake Apple shell.
(The blog post says it doesn't have a fuse, but generally instead of having a seperate fuse the input resistor on these power supplies is a special fusible resistor which is manufactured to also work as a fuse. Saves a few cents and some space at the cost of using a specialist component. Unfortunately it's impossible to tell it apart from a normal resistor just by looking.)