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After a User Dies, Apple Warns Against Counterfeit Chargers
After a Chinese woman was earlier this month evidently electrocuted while talking on her iPhone while it was plugged in to charge, Apple is warning users to avoid counterfeit chargers. From CNet:
"Last week, reports surfaced in China that suggested the woman, Ma Ailun, might have been using a third-party charger designed to look like the real thing. Although third-party chargers are not uncommon, they vary widely in terms of safety and quality.
Earlier this year, safety consulting and certification company UL issued a warning that counterfeit Apple USB chargers were making the rounds and that consumers should be on the lookout for them due to their lower quality and possibly dangerous defects. The company posted the guidance on its site after a woman was allegedly electrocuted while answering a call on her iPhone."
Whether or not the counterfeit charger was the cause, they have reinforced their image and promoted their chargers (as well as discouraging customers from buying their chargers elsewhere).
There are lots of "third-party" Android chargers out there -- ordinary MicroUSB things. If "counterfeit" (i.e. non-Samsung, or whatever) chargers were a problem, wouldn't this happen all the time with Androids?
Sounds like Apple is just taking advantage of the opportunity to scare people into paying the Apple Tax.
No one is being killed by the 5v on the USB bus. The problem is the counterfeit chargers are often poorly designed and can fail in a way that shorts the USB cable to the AC power.
There was an excellent teardown & analysis of a cheap charger last year that pointed out serious safety issues.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
Take a look at a teardown of a fake charger and you'll understand why it can be lethal. The creepage distances in particular are atrocious.
No one is going to die by having 5volts applied to their face.
But they do die from having 220 volts applied to their face.
The issue is that the counterfeit chargers short and deliver the mains directly to the head. It doesn't matter what electronic device is involved. hell, doesn't matter if any electronic device is connected to the end of the other side of the USB cable when the circuit is completed.
Are you saying that China has counterfeit electronics? And that they don't meet safety standards? This simply must be a joke.
Current shmurrent. She died because she wasn't holding it right.
The new "lighting" connector is very solid and handy, contrary to micro USB.
Its designed that way for obvious reasons.
http://en.wikipedia.org/wiki/USB#Mini_and_Micro_connectors
"The Micro plug design is rated for at least 10,000 connect-disconnect cycles—significantly more than the Mini plug design.[38] It is also designed to reduce the mechanical wear on the device; instead the easier-to-replace cable is designed to bear the mechanical wear of connection and disconnection"
, and they contain a bit more than a simple transformer and regulator.
They take the AC line voltage, rectify it to high voltage DC, chop the DC up into high frequency pulses with a MOSFET, step the pulsed voltage down with a specially designed transformer, then rectify the output to low voltage DC. A sample of the output DC is then fed back to the primary side circuitry to achieve closed loop regulation.
Because the primary side of the system is at line potential, the insulation in the switching transformer (and the optocoupler used in the feedback loop) is all that prevents the output side from presenting a shock hazard with respect to earth ground. The quality of construction of many of the Chinese knockoff chargers is downright terrible, and I could easily believe that an insulation breakdown. Dave Jones "EEVBlog" did a teardown of one of these a while back. Scary stuff if you know what you are looking at:
http://www.youtube.com/watch?v=wi-b9k-0KfE
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