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From: ee5391aa@hydra.unm.edu (Duke McMullan n5gax)
Newsgroups: sci.electronics,rec.ham-radio
Subject: New subject: Tesla vs gauss, and other obscure units
Message-ID: <851@ariel.unm.edu>
Date: 30 Oct 89 06:10:23 GMT
References: <1914@sactoh0.UUCP> <28601@buckaroo.mips.COM> <1989Oct29.174631.12960@ux1.cso.uiuc.edu> <1989Oct29.224736.2838@utzoo.uucp>
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Reply-To: ee5391aa@hydra.unm.edu.UUCP (Duke McMullan n5gax)
Organization: University of New Mexico, Albuquerque, NM
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In article <1989Oct29.224736.2838@utzoo.uucp> henry@utzoo.uucp (Henry Spencer)
writes:
>In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu>
mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes:
>>I have been in the science business for over 20 years and have
>>never heard anyone refer to magnetic fields in Tesla - everyone
>>uses gauss...
>>Sometimes it might appear in a textbook (usually directed at
>>freshmen or sophmores - more advanced books use gauss).
>The gauss is the older unit, still used a lot, especially in older sources
>and by older writers.  The Tesla is the correct modern unit; if you look
>around, you'll see increasing use of it in most fields.

Listen well to Henry, my friends. Picofarads have been in use for lothesemany
years, but when I was first getting interested in this stuff (late '50s),
the usage was micromicrofarad, usually abrev.d MMFD. Too, microfarads were
abrev.d MFD. Those fine days are past (Subhan Allah!).

It took several months before I even was able to discover wuthehell MMFD stood
for -- Pop'Tronics ran a nice basic article on capacitors. Still, it was MM
instead of pico for at least ten more years.

Only in the past ten years have nanofarads come into use, and it's still common
to see a cap rated in thousands of microfarads rather than millifarads.

Consider this one: how many hams and other electronikers do you know who pro-
nounce dB dee-bee, and how many of them actually know it means decibel? Then,
how many of them have ever heard of a bel? For the real joker, how many of 'em
know what a bel is? It's a lot easier (IMHO) to explain bels than decibels.
Think again: how often do you see something rated in tens of decibels, rather
than bels? WHY?

Habit, I suspect, coupled with the natural conservatism that we all possess.
This will change. How many people do you know who know the peta- and exa-
prefixes, and the femto- and atto- prefixes? (Admittedly not useful to most
of us, unless you're measuring the circumference of Pluto's orbit in electronic
radii....;^)

We all wear blinders of a sort, lacking omniscience...at least I do; maybe you
know all. But, with improved communication, and the old (unwilling) making
room for the younger, "these, too will pass away."

				Too much rambling; good night.
						d


	I've been to Australia, so now I know what
		the inside of a kangaroo's pouch feels like. -- Anon.
     Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu