Apparently we could use a short history lesson.
Charles Augustine Coulomb
Heinrich Hertz
Alessandro Volta
Andre Marie Ampere
Hans Christian Oersted
Georg Ohm
Michael Faraday
Joseph Henry
Ernst Werner von Siemens
James Prescott Joule
Sir William Thompson, 1st Baron Kelvin
Wilhelm Eduard Weber
Karl Friedrich Gauss
All are people's names, and traditionally are capitalized.
So Volts and Amperes is not stretching it.
Ross Amans
-----Original Message-----
From: Ingraham, Andrew [mailto:Andrew.Ingraham@xxxxxx]
Sent: Friday, April 04, 2003 4:01 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Language conventions
> I seem to remember from my college text books that it mattered if you
> were
> talking about AC or DC voltages/currents/etc. Capitalized letters
> meant
> you were talking about DC values and non-capitalized letters meant AC
> values.
I remember something similar too ... except that this applied to the
variables v(t), i(t), V, I, etc. ... but not the units.
I believe that organizations such as the IEEE have published standards
for things like this. But I do not have a copy.
Personally, I'm fairly flexible, except for a few units. Specifically,
I believe that a lower-case "s" is correct for seconds, whereas
upper-case "S" means Siemens (inverse of Ohms). Engineers frequently
make that mistake, by writing that some delay is so-many "nS", or
nano-Siemens.
Also, I prefer using "m" for milli and "M" for mega. I think that might
be official. Again, people often write things like 50mHz (which would
be a very low frequency), meaning megahertz (or should I say
MegaHertz?).
I have also heard that it's correct to use upper-case for units that are
based on someone's proper name, and lower-case otherwise. That doesn't
work for "voltage" or "amperage" (which IS stretching things a bit), nor
for the milli/Mega distinction, but does seem to work for many others.
In junior high school, a teacher once said to use lower-case for the
Latin prefixes (milli, centi), and upper-case for the Greek(?) prefixes
(Kilo, Mega) ... just because the former prefixes make things smaller
and the latter make them larger.
Along similar lines ... should you use a space between a number and the
unit that comes after it? Is it "5V" or "5 V"? Or "5-V", like the
"2-Watt" example you gave?
Andy
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