Do you feel a tingling sensation in your fingers when you use the trackpad?

Question

I know it sounds like a stupid question...but recently i've been finding more and more i'm feeling a tingling sensation around my fingers when i use my trackpad. Just a few moment ago, my hand was resting on my trackpad(not something that happens often) in any event, my entire hand started to feel like it was getting an electric shock of some kind. I pulled it back real fast.
I'm just wondering has anyone else ever experienced this kind of tingling sensation when using the trackpad?
Thanks

Answer 1

This is indeed noticable, at least to discerning individuals, both on the track pad and on the casing.
I usually call it 'the Roland feeling', as the metal casing of old Roland musical keyboards from this manufacturer had an extremely pronounced 'tingle' to the touch. In the case of Roland, their engineers had not properly understood the concept of grounding. They actually connected the casing via two resistors to both the power outlet phase and ground!
This made the entire case 'float' electrically at 110 V AC in Europe (half the voltage). This sounds dangerous, but it's not the voltage that kills, it's the current, and a voltage connected through a high-ohm resistor can't drive much current through your body. So, while very noticable, to the point of almost making your fingers feel numb, the Roland feeling was never a threat to the player's life.
'The PowerBook feeling' is **extremely** subtle in comparison.
What does it all mean then?
1. The PowerBook casing has a leakage path to an AC voltage source. This leakage path has very high ohmage, and is absolutely nothing to worry about. Don't be too angry at Apple either, because leakage paths are almost impossible to avoid, and it's only the cool aluminium package that makes you notice it. You wouldn't want to trade it for plastic, right?
2. Human fingertips are actually extremely sensitive to electric current! Who would have thunk?
Unplug the power brick, and you'll see that this effect is gone, as the voltage must be AC. A DC voltage of high ohmage will quickly level itself out.