Currently Being ModeratedAug 13, 2010 4:01 PM (in response to carl wolf)Hey Carl,
You could be right, I don't have a passion for electronics or physics in general it has to be said, but it's just I was not necessarily persuaded by your fairly obvious arrogance, well that and some minor research : http://en.wikipedia.org/wiki/Electrostatics
Even without the benefit(?) of studying hole flow theory, I can appreciate that stationary electricity is a vast over simplification. All I am suggesting is that a lack of movement at some level is implied by it's name clearly consisting of electro and static. I am fairly confident that the word 'static' predates the human comprehension of anything electrical, and it's therefor likely that whoever first coined the phrase static electricity employed it accordingly.
I am sure a man like you who presumably collects Higgs bosons for a hobby armed with nothing more than a pair of tweezers while sneering at CERN employees for taking so long - could explain to us why static electricity is named as such.
Or you could call me stupid again.Ipad, iOS 4
Currently Being ModeratedAug 13, 2010 7:51 PM (in response to MaryA in the UK)Hi Mary, just wondering if the charger you used in the end looked like this?
It has a 6 foot cable and looks like that probably has a proper ground pin on the plug.iMac 24"
Currently Being ModeratedAug 14, 2010 2:05 AM (in response to carl wolf)Carl Wolf, are you here on the "support" forum to support or to ridicule and mock?
If you want to look clever, act like nice people like Mary who go overboard to share helpful supportive advice.
Your pathetic ridiculing makes you look dumb, no matter how clever you may be.
The clue is in the word "support".
Message was edited by: ItsadoozyMac Pro, Macbook, iPod Touch, iPhone 3GS, iPad 16G, Mac OS X (10.6.4)
Currently Being ModeratedAug 14, 2010 2:07 AM (in response to Rurouni76)"Hi Mary, just wondering if the charger you used in the end looked like this?
It has a 6 foot cable and looks like that probably has a proper ground pin on the plug."
That charger has the earthed mains lead, so this would definately overcome the issue.Mac Pro, Macbook, iPod Touch, iPhone 3GS, iPad 16G, Mac OS X (10.6.4)
Currently Being ModeratedAug 14, 2010 2:08 AM (in response to Rurouni76)Hi,
It looks just like it, yes... please remember I am in the UK. That link takes me to a U.S. website. I note also you said 'probably' has a ground pin. The supply that came with the original Ipad had a ground pin adapter which was a dummy, not connected to anything. Just because it's there physically doesn't mean it's an actual ground. With respect, you would need to find this out, not assume. Maybe someone from Apple could respond.Mac OS X (10.5.8), iPad, 2iMacs, Macbook
Currently Being ModeratedAug 19, 2010 1:12 AM (in response to MaryA in the UK)Worryingly more reports of tingling ipads!
http://discussions.apple.com/thread.jspa?threadID=2547504&tstart=195Mac Pro, Macbook, iPod Touch, iPhone 3GS, iPad 16G, Mac OS X (10.6.4)
Currently Being ModeratedSep 15, 2010 4:13 AM (in response to Itsadoozy)The iPad charger adapter is stamped double insulated so no chance of a short to the secondary so its safe, and therefore it doesnt require an earth (having taken one to pieces I'm not sure how they can claim it is double insulated!!!)
However Apple have put size and form over function and omited a lot of the electrics that normal transformers have, thats why most 5V 1amp transformers are 3 times the size of the apple one
The upshot of this is that the iPad adapter suffers from a floating ground. ie the 0V rail may or may not be at 0V. It has no real earth reference to tie the 0V to. So the 5V rail may not be at 5v either. In the case of one of mine the 5V rail is at 25v RMS and the chasis (0v rail) is at 20V. As long as the Potential difference between the 2 is 5v the iPad acts normally
Now of course, when you insert the cable into the iPad the chasis makes contact with the 0V rail on the cable and the chassis goes to the level of your 0v reference. Hence if you supplys floating ground is well off then your chassis will become charged. How much depends on a lot of things. If you can feel it also depends on many things including how well you are earthed
The Apple PSU from the MBA etc have better circuitry and therefore the reference voltage is nearer true 0V
Is it dangerous, probably not, looking at the circuitry in the adapter I cant see the drift becoming more than 100v and the current will always be pretty low. Still its a design fault
My worry is when you earth the pad (probably via you) you now had a voltage of in my case +25V supplying the pad, this will either charge it much faster or eventually blow something. One person is claiming 90V floating earth, this is not safe for the iPad and probably not good if you have a pacemaker or are an epilepticLenovo T400, Windows 7
Currently Being ModeratedSep 15, 2010 6:55 AM (in response to Itsadoozy)I've noticed the same problem on MacBook Pros. If you use one while its plugged in to the mains, if you run your finger across its aluminium body, you feel this tingly light vibration in your finger. The sensation goes away as soon as you stop moving your finger.iMac (17-inch, Late 2006), 2GHz, 2GB RAM, 250GB Hard Drive, Mac OS X (10.6.4), iPhone 3GS (16GB), Apple TV (2nd generation)
Currently Being ModeratedSep 16, 2010 8:22 AM (in response to oddballo)Same sensation here too. Even to the point that if you make skin to skin contact with someone touching the iPad the buzzing can be felt on their skin. Also happens with my MacBook pro and the metal bezel on my iPhone 3G.
Currently Being ModeratedDec 5, 2010 8:34 PM (in response to Itsadoozy)Correction to your assertion that static electricity does not pass current. This is completely wrong! Just ask anyone who has been hit with lightening. This example can be in the hundreds of millions of amps. Which is why the recipient tends to die.Currently a Windoze PC, Windows XP Pro
Currently Being ModeratedMar 26, 2011 5:47 PM (in response to Kenfoland)Hello guys,
I have the same tingling feeling.
After having read this thread, I was a little worried. So I took my multi-meter and got a reading. 130 Volt AC between the back of the iPad and my hand. Just for reference: The same reading between me and the wooden desk, as well as my PC's casing was 0.6 VAC.
I live in belgium (220 VAC power sockets) and am using the standard wall charger (2 pins, no earth).iPad, iOS 4
Currently Being ModeratedMar 27, 2011 3:32 AM (in response to Lexie$)FYI, MBP power supply (in the UK) has no earth either. I don't have plain MB so I can not say for sure what that looks like. Regardless of this, if you are plugging in the "figure 8" power cord from a MB into the iPAD "brick" you are still not earthed?
Or did i just missed something?
JerryMPB 13" 7,1 - iPAD2 32G WiFi - iPOD Touch 64G 3rd Gen, Mac OS X (10.6.6)
Currently Being ModeratedMar 27, 2011 5:10 AM (in response to Slammer99uk)I don't have a Mac Book, but I do have a "figure 8" power cord from some other device (2 lines, no earth). I still have the same readings -> drifting AC voltage on the iPad's metal shell.
My guess is as follows: Any exposed metal of a device should be properly grounded. The iPad's shell is probably connected to the ground connection of the power supply (i.e. exposed metal part of iPad connector). It is also common practice to connect the negative line of a DC circuit, which is otherwise free to float around, to ground. Now, if the power supply does not provide a proper grounding, you end up with the exposed metal being connected to the negative DC line which is free to float around compared to earth. When you touch the iPad's shell, standing barefooted on a stone floor (or being earthed otherwise), you are actually yourself grounding the device, conducting a tiny current from the device to earth.
In short: If using the provided equipment, as you should, the iPad's body is not grounded but connected to internal circuits, as it should not!
This is bad design, not poor, bad. If something goes wrong with the power supply (i.e. internal short circuit between AC and DC circuits) you could end up with an exposed metal body delivering full AC.
If no proper grounding can be guaranteed, the shell should be adequately isolated instead of being connected to internal circuits. Never should a person be able to come in contact with exposed electrics. The goal of the wall socket's earth pin is exactly that: ensure that any exposed metal of connected appliances will not pass on any current.
Again, this is just a (fair) guess. If Apple would have shipped a proper grounded power supply, there would be no problem.
I would appreciate it if anybody could confirm my guesses, as I have no intention of disassembling my iPad nor my power supply.
Message was edited by: Lexie$iPad, iOS 4
Currently Being ModeratedMar 27, 2011 5:16 AM (in response to oddballo)"I would appreciate it if anybody could confirm my guesses, as I have no intention of disassembling my iPad nor my power supply."
No disassembly required.
The iPad meets many international standards, including those of the IEC. One of the regulations by that agency is that the product will operate properly with an ungrounded, 2-wire line cord. The electrical voltage on the iPad cover is one-half of the AC line input voltage, at a very low current (which meets international safety standards). The AC voltage on the cover allows the product to meet the FCC Class B limit.I'm in the "Best Thai Movie of 2010". Woohoo!
Currently Being ModeratedMay 31, 2011 12:23 PM (in response to David M Brewer)
A little off topic, but I thought worth mentioning.
David, don't be lulled into thinking what you have read there is a defacto standard. It could kill you.
The point is this, think of your body as a resistor, regardless of how many amps are available, (and the term is amperage I believe), it needs a certain voltage, (also known as Electro Motive Force), to be able to push a current into your body. Current, voltage and resistance are all related as per V=IR, so I=V/R.
A large twelve volt car battery will be able to supply a maximum, (short circuit), current of about 4000 amps yet the voltage at the terminals will never exceed its nominal value by very much. Even on charge it'll be below 14.4VDC. Now your bodys' resistance, (dry fingers), is about 1.5K and therefore the reason that 4000A battery won't kill you is because its resistance means the 14.4V it has available at its terminals is only enough force to squeeze 14.4/1500=0.0096A into your body. If you connect 10 batteries in a long line you will have 120volts available but the current available will be the same, but in this case the current flowing into a part of your body will be 0.08A.
Believe me, virtually every current source you come across will be more than capable of supplying enough current, (0.05A I think), to kill you! Usually and mercifully a protective device will have acted quickly enough to prevent this in the event of a fault.