10 ms·

> 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

by SCdF 6y ago

> 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!

GekkePrutser 6y ago
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.
- huffmsa 6y ago
  You are the ground in this case.
deleted 6y ago
[deleted]
xuki 6y ago
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.
- narrowtux 6y ago
  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.
  - Symbiote 6y ago
    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 https://en.wikipedia.org/wiki/IEC_60320#C5/C6_coupler
    - narrowtux 6y ago
      Yes, but that doesn't include the ground pin.
- Narty 6y ago
  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 :/
michaelcampbell 6y ago
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.
Abishek_Muthian 6y ago
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.
- toxican 6y ago
  My MBP 2019 only has 2 prongs, which I found very odd.
- ricketycricket 6y ago
  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-extension-cable https://www.apple.com/shop/product/MK122LL/A/power-adapter-e...
junon 6y ago
My 2019 macbook did this, I always wondered what it as.
xnyan 6y ago
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.
Gracana 6y ago
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.
- lostlogin 6y ago
  > 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.
  - aembleton 6y ago
    I can't feel it
  - Gracana 6y ago
    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.
- CydeWeys 6y ago
  So then it's two causes, either one of which they could have fixed to prevent the problem.
bfirsh 6y ago
It’s got a name! https://en.m.wikipedia.org/wiki/Electrovibration 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.
xenonite 6y ago
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!
blunte 6y ago
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.

by SCdF 6y ago

GekkePrutser 6y ago

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.

huffmsa 6y ago
You are the ground in this case.

deleted 6y ago

[deleted]

xuki 6y ago

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.

narrowtux 6y ago
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.
- Symbiote 6y ago
  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 https://en.wikipedia.org/wiki/IEC_60320#C5/C6_coupler
  - narrowtux 6y ago
    Yes, but that doesn't include the ground pin.
Narty 6y ago
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 :/

michaelcampbell 6y ago

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.

Abishek_Muthian 6y ago

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.

toxican 6y ago
My MBP 2019 only has 2 prongs, which I found very odd.
ricketycricket 6y ago
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-extension-cable https://www.apple.com/shop/product/MK122LL/A/power-adapter-e...

junon 6y ago

My 2019 macbook did this, I always wondered what it as.

xnyan 6y ago

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.

Gracana 6y ago

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.

lostlogin 6y ago
> 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.
- aembleton 6y ago
  I can't feel it
- Gracana 6y ago
  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.
CydeWeys 6y ago
So then it's two causes, either one of which they could have fixed to prevent the problem.

bfirsh 6y ago

It’s got a name! https://en.m.wikipedia.org/wiki/Electrovibration 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.

xenonite 6y ago

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!

blunte 6y ago

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.