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A comment on Seven years later, I bought a new MacBook. For the first time, I don't love it.

Re:Seven years later, I bought a new MacBook. For the first ... by SCdF on Tuesday June 02, 2020 @07:22AM (#23389853)
> By the way, not including the extension cord is unacceptable. This cord is not only a convenience, but it increases safety, because it's the only way to have earth grounding for the laptop. Without it, rubbing your fingers on the surface of the computer generates this weird vibration due to static.

.... THAT'S WHAT THAT IS?

I have wondered for _years_ why my laptop sometimes feels that way. Another mystery solved!

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Re:Seven years later, I bought a new MacBook. For the first ... by GekkePrutser on Tuesday June 02, 2020 @07:25AM (#23389863)
It's not really static. It's actually induction of the transformer (probably to parts of its shielding) that can't be released to ground.

You can tell because it immediately disappears when you unplug it. Static electricity would take longer to build up. And generally will not build up in metal objects but rather in insulators.

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Re:Seven years later, I bought a new MacBook. For the first ... by huffmsa on Tuesday June 02, 2020 @07:49AM (#23390007)
You are the ground in this case.
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Re:Seven years later, I bought a new MacBook. For the first ... by Gracana on Tuesday June 02, 2020 @09:34AM (#23390814)
As others have said, that's not it. It's the line filter capacitors in the power supply. There's two types: X capacitors which filter differential noise (between line and neutral) and Y capacitors which filter common mode noise (between line and chassis.) Some small AC current (microamps) will pass through the Y capacitor to the chassis. If the chassis is ungrounded, you may be able to feel the current when you touch it.
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Re:Seven years later, I bought a new MacBook. For the first ... by lostlogin on Tuesday June 02, 2020 @09:56AM (#23391014)
> you may be able to feel the current when you touch it.

Are there people who can’t feel it? It really is gross and people comment on it as soon as they touch it.

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Re:Seven years later, I bought a new MacBook. For the first ... by Gracana on Tuesday June 02, 2020 @10:41AM (#23391506)
I don't have a macbook so I can't comment on it, but I have a touhgbook with thinkpad power supply, and I feel it only on my wrists when I'm well grounded. Can't feel it on my fingers or palms.
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Re:Seven years later, I bought a new MacBook. For the first ... by aembleton on Tuesday June 02, 2020 @10:19AM (#23391272)
I can't feel it
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Re:Seven years later, I bought a new MacBook. For the first ... by CydeWeys on Tuesday June 02, 2020 @10:23AM (#23391318)
So then it's two causes, either one of which they could have fixed to prevent the problem.
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Re:Seven years later, I bought a new MacBook. For the first ... by xnyan on Tuesday June 02, 2020 @09:21AM (#23390693)
IEC/UL 60950-1 allows for up to 3.5mA of leakage current to be "accessible" to the user. There are a lot of variations and factors that affect how you feel the sensation of current through your body (how moist your skin is matters a lot), but even microamps can be painful in the right situation.

I love a lot of things about macbooks, but I don't love the non-coated metal for this reason. In addition to the (for me) unpleasant feeling of current, the bottom feels hotter than a coated surface.

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Re:Seven years later, I bought a new MacBook. For the first ... by bfirsh on Tuesday June 02, 2020 @09:43AM (#23390899)
It’s got a name! https://en.m.wikipedia.org/wiki/Electrovibration

As others have said, it’s due to a little bit of current passed through to the outside of the laptop which would otherwise have been passed through ground, not static.

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Re:Seven years later, I bought a new MacBook. For the first ... by michaelcampbell on Tuesday June 02, 2020 @08:03AM (#23390090)
I had a (US) 2015 model that did that, but only in France when I used an adapter that didn't use the third prong.

My family had a faulty refrigerator as a kid with a conductive shell; if you ran your finger down the front if it really quickly (or maybe and/or wet/damp), you'd get more than the "tickle" level of electricity. Scared me. Still does. When my MB did it, I got pretty nervous.

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Re:Seven years later, I bought a new MacBook. For the first ... by blunte on Tuesday June 02, 2020 @10:34AM (#23391428)
Whats (not) fun is having two laptops and not being able to touch them both at the same time because of some grounding difference. With just one, sometimes I feel the electrical vibration. With two, sometimes there is a very uncomfortable zapping sensation in both hands as they each touch a different laptop. It's a bit like if you've ever touched a 9v battery to your tongue, but much stronger.
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Re:Seven years later, I bought a new MacBook. For the first ... by xuki on Tuesday June 02, 2020 @07:42AM (#23389962)
I’m not sure if it’s solved. I used to use the UK plug which always has 3 pins, short or long, and I still get that sometimes.
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Re:Seven years later, I bought a new MacBook. For the first ... by Narty on Tuesday June 02, 2020 @07:59AM (#23390066)
Check inside the 3 pin plug adaptor. The bit that slides onto the metal disc is just plastic on some plugs and therefore isn't earthed :/
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Re:Seven years later, I bought a new MacBook. For the first ... by narrowtux on Tuesday June 02, 2020 @07:59AM (#23390065)
Any clue if there's a version for german plugs with ground pins (schutzkontaktstecker) for the duckhead? I like not having an additional cable going from the AC to the outlet, but not having the computer connected to ground means that there are some problems, including static noise on headphones, and this "rubbing" sensation.
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Re:Seven years later, I bought a new MacBook. For the first ... by Symbiote on Tuesday June 02, 2020 @10:10AM (#23391170)
The transformer end is a standard IEC connector (C5 I think, I don't have a Mac). You can use any appropriate cable, e.g. a 30cm one if you can find it.

I doubt there's one that fits on the transformer. The UK socket will only accept a plug with an earth pin as one of the safety features, so there's no opportunity to cut cost here.

https://en.wikipedia.org/wiki/IEC_60320#C5/C6_coupler

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Re:Seven years later, I bought a new MacBook. For the first ... by narrowtux on Wednesday June 03, 2020 @02:49AM (#23400657)
Yes, but that doesn't include the ground pin.
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Re:Seven years later, I bought a new MacBook. For the first ... by Abishek_Muthian on Tuesday June 02, 2020 @09:10AM (#23390591)
Does the current MacBook come with 3 prong plug with ground pin? My iPad Air 2 doesn't and it does have this issue when touching the aluminium when charging.
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Re:Seven years later, I bought a new MacBook. For the first ... by ricketycricket on Tuesday June 02, 2020 @10:28AM (#23391364)
I believe only the extension cord has grounding, not the adapters that plug on to the power supply. US version: https://www.apple.com/shop/product/MK122LL/A/power-adapter-e...
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Re:Seven years later, I bought a new MacBook. For the first ... by toxican on Tuesday June 02, 2020 @09:59AM (#23391040)
My MBP 2019 only has 2 prongs, which I found very odd.
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Re:Seven years later, I bought a new MacBook. For the first ... by xenonite on Tuesday June 02, 2020 @10:06AM (#23391135)
Using the grounded extension cord finally connects the HiFi USB sound card without static noise! Wow, this is so great, I have totally overlooked this!
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Re:Seven years later, I bought a new MacBook. For the first ... by junon on Tuesday June 02, 2020 @09:17AM (#23390655)
My 2019 macbook did this, I always wondered what it as.
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