Electronics > Beginners
New 2017 Macbook Pro 15 Inch giving me static electric shock. Is it normal?
Gyro:
Who knows :-// Historical reasons? I guess only the manufacturers could have an answer for that. I could pull out an equal number of caps from my parts box that use the correct notation, those that don't use IEC notation of course. At least the US maufacturers seem to have stopped using mF when they mean uF. It's certainly something you don't want people littering new schematics with.
The above is no excuse for us not using and promoting correct engineering notation here though, particularly for fundamentals like voltage and current.
P.S. I see 100nF used a lot more than 0.1uF in discussion and schematics, I certainly don't see 0.01uF used instead of 10nF these days (as used to be common in the past). maybe a geographical thing.
@nasserprofessional: Sorry for the diversion.
bd139:
I noticed this. Americans historically used mmf and mf as measurements of capacitors (pF and uF) only and half the time they don't even add the units. This seems to have turned into a defacto standard in American literature. Then you have to decipher whether "47" means 47pF or 47uF. Here in Europe we adopted all of the correct symbols: F, mF, uF, nF, pF. 47u, 47p. Problem solved. Ultimately there should be no leading decimal portion of the number - just use the correct units!
Again diversion off :)
Just measured current between my ThinkPad T440 and ground: 82uA.
And the MacBook again: 103uA
Now my desk lamp which is a cheap shitty switch mode driven LED thing: 8uA.
Now I'm soaking wet after having just got out of the shower so not the best time to measure this :palm:
RGB255_0_0:
--- Quote from: bd139 on August 31, 2017, 09:52:49 am ---Ultimately there should be no leading decimal portion of the number - just use the correct units!
--- End quote ---
I prefer the decimal point. Sometimes I go blind to the p/u/m if there are so many and have to go back and correct it :palm:
At least if you stick to, say, micro you don't even need to read the postfix.
Maybe I'm careless. :-DD
Gyro:
--- Quote from: RGB255_0_0 on August 31, 2017, 10:14:17 am ---Maybe I'm careless. :-DD
--- End quote ---
Yep :P ....Or just old like me!
electrolust:
--- Quote from: wraper on August 30, 2017, 08:47:44 am ---
--- Quote from: electrolust on August 30, 2017, 06:21:39 am ---You changed the prefix (for some reason), and this is the beginner section. So no, it was not obviously a typo. For example, it wasn't obvious to me, a beginner. :-//
--- End quote ---
:palm: |O I changed units for a reason that uA may look like very small current for some people (beginners). If I quote a current value, and write the same value but in different units and miss a letter while typing, it's a typo. The fact that something is not obvious to you, means only that you should learn more. Not that a typo magically stops being a typo.
--- End quote ---
huh?
I didn't say it wasn't a typo. I said it wasn't obviously a typo. I don't know what the palm is about buddy, get over yourself.
It was an error and it wasn't obvious if, as a beginner with no gauge of what is "big" current esp wrt the human body, it was an error in units (a typo) or an error in quick reading (a thinko). 0.25mA also looks like "very small current", to a beginner without an appreciation of a milliamp. In fact due to the decimal it "looks" smaller than 250uA (no decimal), so I think you went the wrong direction if your intent was to make the value look "bigger".
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