I recently spent 6 months or so in Europe and noticed the sensation using a power converter from my US power adapter to UK. Back in the US, I don't feel the tingling sensation. Almost positive it has something to do with different power infrastructure/plugs in different countries.
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current leakage on MBA
- Thread starter anand.rohira
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If you only have the two supply lines (neutral and phase) the potential of the outgoing ground to the macbook from the power converter may drift since there is no known ground reference. I.e. the common mode voltage of the + and - signals going to the macbook will be floating. I'm not sure why, but the common mode voltage often stays somewhere at 1/2 the outlet voltage. Probably has something to do with typical switched power supply topologies.
If you connect a third known safe potential (in this case, ground), the - pin going to the macbook can be connected to this potential which means that there will be no common mode voltage that feels uncomfortable.
The reason why the common mode voltage (lets say 150 volts) is harmless is because the maximum current is rather low.
If you connect a third known safe potential (in this case, ground), the - pin going to the macbook can be connected to this potential which means that there will be no common mode voltage that feels uncomfortable.
The reason why the common mode voltage (lets say 150 volts) is harmless is because the maximum current is rather low.
Hey Anand!
I'm from India as well, and a recent proud owner of an Air.
I understand what you mean. That happens to me as well when earthing isn't proper, OR I plugin the power source to 2-pin power source.
I've had that but on my iPad 2. I'll be getting my Macbook Air around the 20th and I'll also report on that ! 
It is this fact which makes me think it is due to vibrations caused by a fan, rather than electricity spilling out over the machine. The effect is only felt by a moving finger. BUt the effect ceases when the power is disconnected.
But current transfers through persons?
I agree that the phenomenon is only noticeable when the finger is moving, but the fact that it also occurs when running a finger across the skin of a person touching the plugged-in MacBook (without touching the machine yourself), convinces me that the phenomenon is electrical.
I agree that the phenomenon is only noticeable when the finger is moving, but the fact that it also occurs when running a finger across the skin of a person touching the plugged-in MacBook (without touching the machine yourself), convinces me that the phenomenon is electrical.
Hmm. You are right, if it works via another person it must be electricity based. I shall test this out.
What you are feeling
I'm on my 3rd MacBook Air in 4 weeks. The first 2 had other problems but not this particular problem. I'm an Electrical Engineer and am forced to use this thing for work. What you are actually feeling is about 5 Volts AC lingering on the case of the computer. I measured it so it's not the fan, not the paint job, but real live electricity that's leaking onto the case and into your body. Yeah, the 3 prong cable "masks" the problem, as does being an Apple fanboy or not knowing the first thing about electricity. Unfortunately, the fact is that this is a flaw and one that probably isn't so good for you.
I'm on my 3rd MacBook Air in 4 weeks. The first 2 had other problems but not this particular problem. I'm an Electrical Engineer and am forced to use this thing for work. What you are actually feeling is about 5 Volts AC lingering on the case of the computer. I measured it so it's not the fan, not the paint job, but real live electricity that's leaking onto the case and into your body. Yeah, the 3 prong cable "masks" the problem, as does being an Apple fanboy or not knowing the first thing about electricity. Unfortunately, the fact is that this is a flaw and one that probably isn't so good for you.
How does this work exactly ... the masking bit? If you have 5V DC going to the case and you earth the AC on the other side of a transformer, why would that stop the tingle? It's been a while since I studied electronics at college but I can't see why this should make a difference.
BTW: If you use the long cable on the other end of the transformer then it has an earth connection, all the other adaptor plugs do not ... this would appear to be a design flaw.