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Girl (Said to be) Electrified to Death by a Charging iPhone 4

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#46 Astra.Xtreme

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Posted 15 July 2013 - 15:01

you have to remember, there has to be a path to the brain, or the heart. with mains, its easy for the electricity to path through your heart,because if you're grounded with your feet for example, and you touch a live wire, the electricity will pass through your arm down to your feet,making it likely your heart will be in the path.  if you make a cut on 2 fingers on your left hand,and insert a 5v 1a probe on one finger,and ground on the other, the only thing you'll do is burn your hand,as electricity travels on the path of least resistance. this ground is called floating,as it is not the same ground as mains ground is(since its totally isolated in the charger/device),and this ground only exists inside the charger/device, so electricity will not flow through your hand to your feet like mains did,it will flow from one finger on your left hand,to the other finger on your left hand,taking the path of least resistance.

Why are you assuming a floating ground would be attached to a finger?  All the phone chargers I've seen aren't grounded.




#47 vcfan

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Posted 15 July 2013 - 15:09

Why are you assuming a floating ground would be attached to a finger?  All the phone chargers I've seen aren't grounded.

 

what do you mean arent grounded? they have a floating ground,which is the 0v reference return path for the 5v coming from the other end. what im saying is, unless you stick the positive end onto one side of your body,and the negative end on the other side of your body, this 5v 1a will never electrocute you,because there isn't a path to your heart,or brain, like the example I used earlier where I said,if you short your 2 fingers,the only thing that would happen is that you would burn your hand,because the electricity is taking the path from one finger directly to the next.

 

AND this is assuming the mains portion is working properly. if the mains portion shorts to the output portion, then you can easily get electrocuted just by touching one of the wires,and being grounded to earth, but we're not talking about this scenario. we're strictly speaking about the theoretical potential of being electrocuted by 5v 1a.



#48 Astra.Xtreme

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Posted 15 July 2013 - 15:34

what do you mean arent grounded? they have a floating ground,which is the 0v reference return path for the 5v coming from the other end. what im saying is, unless you stick the positive end onto one side of your body,and the negative end on the other side of your body, this 5v 1a will never electrocute you,because there isn't a path to your heart,or brain, like the example I used earlier where I said,if you short your 2 fingers,the only thing that would happen is that you would burn your hand,because the electricity is taking the path from one finger directly to the next.

 

AND this is assuming the mains portion is working properly. if the mains portion shorts to the output portion, then you can easily get electrocuted just by touching one of the wires,and being grounded to earth, but we're not talking about this scenario. we're strictly speaking about the theoretical potential of being electrocuted by 5v 1a.

Okay, I see what you're saying.  I misread your previous comment.

 

But if we take the situation into perspective, it's pretty safe to assume that the charger was faulty.  So the 5V regulator wasn't functional thus probably making the metal frame on the iPhone live with 220V.  And since she was answering the phone, she probably had it touching her face, which obviously is a very vulnerable area on the body.

 

The real question here is where the failure point is.



#49 vcfan

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Posted 15 July 2013 - 15:38

Okay, I see what you're saying.  I misread your previous comment.

 

But if we take the situation into perspective, it's pretty safe to assume that the charger was faulty.  So the 5V regulator wasn't functional thus probably making the metal frame on the iPhone live with 220V.  And since she was answering the phone, she probably had it touching her face, which obviously is a very vulnerable area on the body.

 

The real question here is where the failure point is.

 

exactly, so the isolation part must have failed,and the live portion was shorted to the regulated portion, thus she could have been exposed to a live wire,and have been grounded to earth,and she got electrocuted.



#50 Astra.Xtreme

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Posted 15 July 2013 - 15:41

exactly, so the isolation part must have failed,and the live portion was shorted to the regulated portion, thus she could have been exposed to a live wire,and have been grounded to earth,and she got electrocuted.

 

Agreed.



#51 vcfan

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Posted 15 July 2013 - 15:44

ive also cracked open apple chargers,and the design is very safe,it isn't a design issue at all. my theory is that a component,such as a resistor popped off inside,and shorted the 2 ends.



#52 vetneufuse

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Posted 15 July 2013 - 15:51

You do realise that using a phone while its charging damages the battery, that is why the cables are so short.

uh no... they have switching circuits when a phone is plugged in the charger uses transistors to switch current flow so it can charge the battery and simultaneously NOT use the battery for phone operation... the second the cord is pulled that gate switches back instantly to battery power... hence why you can do what you do... this circuit also senses the switch, hence why the phone knows its on AC or Battery, and switches on another sensor circuit that senses the charge... it's a pretty simple concept if you look at the schematics for it



#53 The_Decryptor

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Posted 16 July 2013 - 00:36

ive also cracked open apple chargers,and the design is very safe,it isn't a design issue at all. my theory is that a component,such as a resistor popped off inside,and shorted the 2 ends.


Or she had a knock off charger, some of those are scary as well.

She was also in the shower at the time and stepped out to answer it, so that would definitely affect it.

#54 OP +FaiKee

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Posted 16 July 2013 - 01:12

The Chinese Police had a preliminary inspection of the charger and wire and found that it's in intact and working condition. I guess they want to wait for Apple tech guys to open up the phone, so Apple couldn't say a 3rd party had tempered with it and try to get away.

 

iphones have integrated batteries, and the girl's family said it was bought last year, unlikely there is a home-made battery that caused the accident.

 

Apple's only hope is if they found the phone had been "repaired" by a unauthorized shop.



#55 Shiranui

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Posted 16 July 2013 - 02:04

Saw this on the news. Probably a dodgy Chinese-made third-party charger, but even so, I don't see how the case could have become live, especially not with the 220V mains voltage rather than the 5 or so from the charger.

 

Anyway, I have received 240V shocks from the mains on 4 occasions in my life -- the first being when I was about 3 years old -- and I have survived each time. I must be immortal.



#56 The_Decryptor

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Posted 16 July 2013 - 02:24

From the front page article on this subject.

BPPKraxCIAACC4A.png:large

That's not an Apple charger, that's a knock off. If that's the real charger she was using then it's not Apple's fault (Even though it already wasn't)

#57 OP +FaiKee

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Posted 16 July 2013 - 02:59

From the front page article on this subject.

*** snip ****

That's not an Apple charger, that's a knock off. If that's the real charger she was using then it's not Apple's fault (Even though it already wasn't)

Yes you are right, when the video came out , many people already pointed out that it's not the charger provided by Apple China stores, so the story now goes into a interesting turn. :)



#58 vcfan

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Posted 16 July 2013 - 04:19

I made a little mspaint block diagram of the apple charger

LtNINXU.png

 

pretty standard design, but the isolation boundary is adequate. it prevents arcing,and components shorting. the cheap chargers ive seen have like either 1/6 the isolation boundary compared to apple,samsung,etc. or no boundary at all. hell I've seen chargers not even use a transformer,just some resistors,caps and some diodes. the UL or certification markings are mostly fake. im surprised we're not hearing more of these incidents,because these knockoff chargers can be had for only a dollar on ebay,and they sell a ton of them.



#59 OP +FaiKee

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Posted 16 July 2013 - 05:30

I made a little mspaint block diagram of the apple charger

 

** snip **

 

pretty standard design, but the isolation boundary is adequate. it prevents arcing,and components shorting. the cheap chargers ive seen have like either 1/6 the isolation boundary compared to apple,samsung,etc. or no boundary at all. hell I've seen chargers not even use a transformer,just some resistors,caps and some diodes. the UL or certification markings are mostly fake. im surprised we're not hearing more of these incidents,because these knockoff chargers can be had for only a dollar on ebay,and they sell a ton of them.

Tks for the detail chart, but one question: transformer only works on a/c, should the rectifier be after step down?



#60 vcfan

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Posted 16 July 2013 - 05:41

Tks for the detail chart, but one question: transformer only works on a/c, should the rectifier be after step down?

the transformer control circuit does switching on the dc supply at the input,so it turns it basically into ac. And I simplified the diagram, but the ac is rectified with a diode at the output to give dc