PowerDeathTrap?!
#16
Posted 22 February 2003 - 07:29 AM
Folks, what we humans detect is currrent, not voltage. your body could be at 2500V and so long as you were no grounded, you'd be fine. This is why birds can land on power lines without exploding. However, there is a relationship between voltage and current determined by Ohm's law as V=IR, where V is volts, I is current and R is resistance. When people become part of an electrical circuit, the body acts mostly like resistance ® and luckily, our bodies are generally poor conductors which means R is big - unless we are wet which tends to lower our resistance. That's why you can feel a charge when you touch a 9v to your tongue but not your arm (well - also the tongue is much more sensitive than the skin on your arm). It's also current that kills, not voltage, and in fact, the amount of current required to kill a human is very small (~ 0.07 amps). But the path of the current through the body plays a role too - 0.07 amps from pinky to thumb on one hand won't do it but from one had to the other could since the current could then affect the heart.
As mentioned, the computer could be acting as a big capacitor which could cause a large current to discharge when the person who touches it is at a different potential (V) than the case of the computer. In this case, the formula for the amount of charge you'd feel is I=C(dv/dt) where I is current, C is capacitance, and dv/dt is the change in voltage w.r.t. change in time. C is determined by C = Q/V, where Q is amount of charge on case of PB and V is voltage of case (V here is probably ~5V). Basically, dt can be assumed to be very small, << 1 sec. for a static discharge and small dt means bigger I - this helps to explain why we feel static electric shocks (although dv is usually big too with static discharge).
Now, Apple Newbie, try this experiment: ground yourself before touching your powerbook by touching a metal plumbing fixture first (most plumbing is connected to earth ground). This should get your body to near ground (V=0). Then try to touch your PB with it powered using only battery power. Do you get the same charge? I suspect that static discharge is playing some role in your situation but it is remotely possible that it is just the PB causing the shock.
Best Wishes.
As mentioned, the computer could be acting as a big capacitor which could cause a large current to discharge when the person who touches it is at a different potential (V) than the case of the computer. In this case, the formula for the amount of charge you'd feel is I=C(dv/dt) where I is current, C is capacitance, and dv/dt is the change in voltage w.r.t. change in time. C is determined by C = Q/V, where Q is amount of charge on case of PB and V is voltage of case (V here is probably ~5V). Basically, dt can be assumed to be very small, << 1 sec. for a static discharge and small dt means bigger I - this helps to explain why we feel static electric shocks (although dv is usually big too with static discharge).
Now, Apple Newbie, try this experiment: ground yourself before touching your powerbook by touching a metal plumbing fixture first (most plumbing is connected to earth ground). This should get your body to near ground (V=0). Then try to touch your PB with it powered using only battery power. Do you get the same charge? I suspect that static discharge is playing some role in your situation but it is remotely possible that it is just the PB causing the shock.
Best Wishes.
#17
Posted 22 February 2003 - 07:50 AM
I'm with Caelth, I think someone is jerking our chain. This person's way too cool to have just dropped $2000+ on a computer by a manufacturer he's never used before and have it zapping him and his family right away. And then to have a tagline that says " I love my new Apple Mac Computer!". Plus, my 15" keyboard has non metallic keys (read non conducting).
#19
Posted 22 February 2003 - 11:52 AM
Probably the eraser and wood aren't enough insulators. After all it's POWERBook /forums/ubbthreads/images/graemlins/wink.gif
He gets shocked through the graphite core. I suggest using porcelain mug's edge to press that power button with /forums/ubbthreads/images/graemlins/cool.gif
He gets shocked through the graphite core. I suggest using porcelain mug's edge to press that power button with /forums/ubbthreads/images/graemlins/cool.gif
#21
Posted 22 February 2003 - 04:37 PM
Oh man, that's crazy. what I would suggest is that : take oven gloves, and take off the SuperPowerBook's battery. (And then, put your tongue on the battery to see if it's still good /forums/ubbthreads/images/graemlins/wink.gif lol I'm kidding)
That's what I would do.
That's what I would do.
#22
Posted 22 February 2003 - 05:23 PM
In reply to:
I love my new Apple Mac Computer!
I love my new Apple Mac Computer!
Apple_Newbie:
How do you know? If this is your first Mac and you aren't joking (which I think you are) how would you know that you like it? BTW thanks for the lecture dakota (seriously, I learned something). I think that the story and signature are just too fake. Good story though.
Ryan
#24
Posted 23 February 2003 - 10:56 AM
The highest voltage that exists anywhere in your laptop computer is that which comes out of the power adaptor. My iBook's power adaptor puts out 24 volts. Ti-Books use the same adaptor. I imagine that all current Apple laptops use the same.
If there was any more than that coming out of the power plug it would damage the computer for sure. It's safe to say that if there was enough voltage coming out of that plug to give you a substantial shock just from touching the computer the whole machine would have long-since gone up in a puff of smoke.
The only other way for the computer to give you a shock would be for the electricity to come from another source. Either you have the computer touching something that is electrically live or you have one hell of a static electricity problem. Either way, the risk that the computer would self-destruct upon exposure to that kind of voltage is so great that you, likely, would have a dead computer on your hands right now.
I can't say with great authority that we are being lied to but I will say I smell a snow-job.
If you REALLY ARE telling the truth, the answer is simple. You have a defective computer. In fact, you have a 1 in 1,000,000 kind of a defect. Call Apple and tell them your story and have them replace the computer.
If it really IS defective they will replace it in a heartbeat.
If there was any more than that coming out of the power plug it would damage the computer for sure. It's safe to say that if there was enough voltage coming out of that plug to give you a substantial shock just from touching the computer the whole machine would have long-since gone up in a puff of smoke.
The only other way for the computer to give you a shock would be for the electricity to come from another source. Either you have the computer touching something that is electrically live or you have one hell of a static electricity problem. Either way, the risk that the computer would self-destruct upon exposure to that kind of voltage is so great that you, likely, would have a dead computer on your hands right now.
I can't say with great authority that we are being lied to but I will say I smell a snow-job.
If you REALLY ARE telling the truth, the answer is simple. You have a defective computer. In fact, you have a 1 in 1,000,000 kind of a defect. Call Apple and tell them your story and have them replace the computer.
If it really IS defective they will replace it in a heartbeat.



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