Tiny, cheap, and dangerous: Inside a fake iPhone charger
righto.com
righto.com
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.)
Hardly a re-assurance now, is it?
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.
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.
EDIT: I don't use this charger anymore, just to be clear.
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.
They seem to have good reviews across their range of products and have certification logos. However, I've been hesitant.
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).
I bet the same thing was happening with the XBox controller adapters.
With this things, I've put reliabillity and safety as key determinant.
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.
I'm the author of the original post and I've torn apart and analyzed a lot of chargers if you want to see the differences between them: http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-ap...