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From: koning@koning.dec.com (Paul Koning)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Re: Tesla vs gauss, and other obscure units
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Date: 30 Oct 89 20:07:53 GMT
References: <30339@buckaroo.mips.COM> <1914@sactoh0.UUCP> <28601@buckaroo.mips.COM> <1989Oct29.174631.12960@ux1.cso.uiuc.edu> <1989Oct29.224736.2838@utzoo.uucp> <851@ariel.unm.edu>
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Tesla is the SI unit, gauss the (officially obsolete) unit from the
CGS system.  Why is it still used?  Partly because we're in the USA,
where the metric system is only barely understood.  Partly because
engineers and amateurs tend not to care much about consistency in
units.

I still remember the grief I caught from my Physics prof. because I
had the nerve to write up a lab report on gamma ray experiments with
the energies listed in fJ (femtojoules) rather than his pet MeV 
(megaelectronvolts, a mishmash if ever I saw one).

Does all this matter, you ask?  It sure does.  I recently tried to 
read an apparently well-regarded textbook on switching power supplies.
The section on inductor design was totally unintellegible.  The 
reason: careless random mixing of units, particularly centimeters
or square centimeters vs. "circular mils" [sic].

         paul, ni1d

PS. Remember the Hz vs. cps flaming in QST some years ago?