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USB shock hazard!?

Monu Tripathi
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Joined: Oct 12, 2008
Posts: 1369
    
    1

I attached HTC HERO to the USB drive of my Desktop PC and felt a mild shock (have noticed this in laptops too). I wonder if you actually can get electrocuted...

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Ankit Garg
Sheriff

Joined: Aug 03, 2008
Posts: 9321
    
  17

Electrocution by USB, that's new


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Pat Farrell
Rancher

Joined: Aug 11, 2007
Posts: 4659
    
    5

Are you sure it wasn't just a static discharge? USB is defined as 5V and no more than 500 milliAmps. That's less than a 9v battery can deliver.
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11499
    
  16

if you put a 9v on your tongue, it feels like an awful lot! I wouldn't dismiss that quite so casually.


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Pat Farrell
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Joined: Aug 11, 2007
Posts: 4659
    
    5

fred rosenberger wrote:if you put a 9v on your tongue, it feels like an awful lot!

Yeah, I used to do that as a kid.

But usually, the skin's normal resistance won't allow noticeable current to flow at voltages under 12V or so. Your tongue is wet and has salts so its a lot more conductive.

The numbers are pretty amazing, just a couple of volts and a few hundred miliamps across your heart will kill you. But usually humans don't push electricity across their own hearts.

If your hands are wet, or worse, wet with salt water, then things are different.
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11499
    
  16

Pat Farrell wrote:Yeah, I used to do that as a kid.

Kid? I do it now...it's the easiest way to tell if the battery is still good or not.
W. Joe Smith
Ranch Hand

Joined: Feb 10, 2009
Posts: 710
Pat Farrell wrote:

The numbers are pretty amazing, just a couple of volts and a few hundred miliamps across your heart will kill you.



I think it is 6 milliamps...or was it 60? I know it was very low. Which is crazy because at my old job I had to hook up power cables to a 400 amp company switch on the stage to power all the lights and stuff.


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Pat Farrell
Rancher

Joined: Aug 11, 2007
Posts: 4659
    
    5

Yeah, don't quote me on the exact milliamp value, its really low. I remember it was lower than the 100 milliamps that a standard "watch" battery, such as a CR2530 can deliver.
Ryan McGuire
Ranch Hand

Joined: Feb 18, 2005
Posts: 1013
    
    3
fred rosenberger wrote:
Pat Farrell wrote:Yeah, I used to do that as a kid.

Kid? I do it now...it's the easiest way to tell if the battery is still good or not.


9 volt battery. Feh.

Previous discussion
Vikas Kapoor
Ranch Hand

Joined: Aug 16, 2007
Posts: 1374
Might be because of improper earthing? Did you face the same issue with your fridge/TV?
Frank Silbermann
Ranch Hand

Joined: Jun 06, 2002
Posts: 1390
Monu Tripathi wrote:I attached HTC HERO to the USB drive of my Desktop PC and felt a mild shock (have noticed this in laptops too). I wonder if you actually can get electrocuted...
I'm sure you can. See:

http://www.youtube.com/watch?v=xz3u8IsHCB8
Monu Tripathi
Rancher

Joined: Oct 12, 2008
Posts: 1369
    
    1

Vikas Kapoor wrote:Might be because of improper earthing? Did you face the same issue with your fridge/TV?

No
Deepak Bala
Bartender

Joined: Feb 24, 2006
Posts: 6662
    
    5

Monu Tripathi wrote:
Vikas Kapoor wrote:Might be because of improper earthing? Did you face the same issue with your fridge/TV?

No


You need to bury your laptop under 1 feet of top soil to ensure proper earthing. Did you do that ? No ? Thought so


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Vikas Kapoor
Ranch Hand

Joined: Aug 16, 2007
Posts: 1374
Deepak Bala wrote:
Monu Tripathi wrote:
Vikas Kapoor wrote:Might be because of improper earthing? Did you face the same issue with your fridge/TV?

No


You need to bury your laptop under 1 feet of top soil to ensure proper earthing. Did you do that ? No ? Thought so


That would only solve laptop issue. I have complete solution.

      
Deepak Bala
Bartender

Joined: Feb 24, 2006
Posts: 6662
    
    5

This is also becoming a popular technique to avoid shocks

Monu Tripathi
Rancher

Joined: Oct 12, 2008
Posts: 1369
    
    1

Deepak Bala wrote:This is also becoming a popular technique to avoid shocks


and allergies too!

You are also using it to hijack this thread and post images of your secretary playing in mud!
 
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subject: USB shock hazard!?