71–80 of 165 posts
I have this problem in India. I suspected the mains was dodgy, because during the many power outages i never got the shocks when on UPS. I got a multimeter and measured. The neutral was 70V and the phase 300ish. So the difference was roughly 230V but a switched power adapter would make this hover around 70 too (I believe an old coil based would probably been fine). The Indian electrician didn't understand my problem…
I have this problem in India. I suspected the mains was dodgy, because during the many power outages i never got the shocks when on UPS. I got a multimeter and measured. The neutral was 70V and the phase 300ish. So the difference was roughly 230V but a switched power adapter would make this hover around 70 too (I believe an old coil based would probably been fine). The Indian electrician didn't understand my problem…
This vacuum had the most five-star reviews on Amazon, but then a minority of people started complaining and leaving one-star reviews, saying they were getting shocked.
The reactions from the fanboy crowd were non-sympathetic ("you're imagining it," "it's just static," etc.), and they mass downvoted every one-star review. Some of the people claimed they were getting shocked PRETTY HARD, too, as in it knocked them over. IIRC, even Shark responded saying that it was impossible for the vacuum to shock you.
I remember seeing this while looking at vacuums for my elderly mother who has a heart condition. To the electrical engineer in me, everything made sense!
I started defending every single one-star reviewer person, and I wrote my own very detailed review with photos of the handle. Soon, the tide turned, and more people started upvoting my review than downvoting it; and I even received personal "thank you" messages from the people who got shocked ("finally someone believes me").
It eventually got to the point where a year later in 2014, Shark released an updated model with no more metal strip. Seeing this, I bought the new model for my mother. I'd like to think I can give myself SOME credit for causing them to do that.
Not only that, the upvotes from that alone were a good part of the reason I became an Amazon Top Reviewer.
Don't use Macs but I'm surprised Apple apparently didn't give an earthed power adapter by default on a metal skin product. This seems like negligence. Now that I think about it, my iPad's the same when charging.
They do give one by default, but you can disconnect it if you so choose. FWIW, I have never had a problem using the two pronged plug in the US. It's interesting to see all this preexisting problems with MacBooks surfacing after the recent release of the MBP
Earlier quoted context omitted.
Well that explains what the weird feeling I used to feel when touching a 2015 Macbook I was using last year. It felt exactly like that (as though the surface was bumpy) though I never got far enough into debugging it to figure out that it was actual charge leakage onto the case and that I was feeling the AC current. That's a bit scary. Question: aren't laptops powered off DC (there's a rectifier/transformer combo in…
Laptops are indeed powered off of DC, which means that there will be a constant voltage measured across the positive and negative pins of the MagSafe plug. However, the voltage measured from either pin to ground might very well fluctuate. Without the grounding pin on the power supply, the DC side of the supply may 'float' with respect to earth ground. If you plot the voltages measured from each pin to ground, it prob…
What's fascinating to me about this phenomenon is that you can actually feel the 60Hz AC by running your hand across the lid. It feels as if the surface is slightly bumpy, but the width of the bumps changes as you adjust the speed your finger moves. Unplug from mains, and the surface becomes smooth. As the answer notes, this only happens when using the two-prong adapter without earthing. It also seems to be more noti…
I felt this on an Apple laptop in California a couple of years ago, in an apartment with only two-prong outlets in it. I'd describe the feeling more like the laptop cover was vibrating, rather than bumpy. The feeling went away and the laptop cover became smooth and normal if I lifted my feet off of the ground. Once all the outlets were rewired to be three-prong, with ground, I used a three-prong power cord and the pr…
In Japan, two prong outlets make up the vast majority of sockets, it kinda sucks.
As an aside, I should buy a lottery ticket given the number of rare issues that happen to my Apple products.
Earlier quoted context omitted.
They do give one by default, but you can disconnect it if you so choose. FWIW, I have never had a problem using the two pronged plug in the US. It's interesting to see all this preexisting problems with MacBooks surfacing after the recent release of the MBP
They stopped as of the new MacBooks this month :/
Earlier quoted context omitted.
I felt this on an Apple laptop in California a couple of years ago, in an apartment with only two-prong outlets in it. I'd describe the feeling more like the laptop cover was vibrating, rather than bumpy. The feeling went away and the laptop cover became smooth and normal if I lifted my feet off of the ground. Once all the outlets were rewired to be three-prong, with ground, I used a three-prong power cord and the pr…
> and scary to think that two-prong outlets and appliances are legal anywhere In Japan, two prong outlets make up the vast majority of sockets, it kinda sucks.
What's fascinating to me about this phenomenon is that you can actually feel the 60Hz AC by running your hand across the lid. It feels as if the surface is slightly bumpy, but the width of the bumps changes as you adjust the speed your finger moves. Unplug from mains, and the surface becomes smooth. As the answer notes, this only happens when using the two-prong adapter without earthing. It also seems to be more noti…
FYI, I can't remember which way round it is, but only some of the UK 3-pronged adapters are actually earthed (as I discovered after having this problem myself). I think it's the extension cord that is properly earthed, whereas just the plug attachment that goes directly into the power brick is not. You can tell by looking up into the adapter (the part that plugs into the power brick) and seeing if it's metal or plast…
