vaso@mips.COM (Vaso Bovan) (10/30/89)
In article <851@ariel.unm.edu> ee5391aa@hydra.unm.edu.UUCP (Duke McMullan n5gax) writes: > >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? > The bel is of rather recent vintage, 1923 [ A Dictionary of Scientific Units, 4th Ed., Chapman & Hall, 1980]. This source contains the statement that "in continental Europe, the neper is used instead of the bel." Is this true, European readers ?
koning@koning.dec.com (Paul Koning) (10/31/89)
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?jgh@root.co.uk (Jeremy G Harris) (10/31/89)
In article <30339@buckaroo.mips.COM> vaso@mips.COM (Vaso Bovan) writes: >The bel is of rather recent vintage, 1923 [ A Dictionary of Scientific Units, >4th Ed., Chapman & Hall, 1980]. This source contains the statement that "in >continental Europe, the neper is used instead of the bel." Obsolete, I think. A faint memory tells me that the neper is natural-log based rather than log-base-10 based. Never seen it used. -- Jeremy Harris jgh@root.co.uk
torkil@psivax.UUCP (Torkil Hammer) (11/01/89)
In article <30339@buckaroo.mips.COM> vaso@mips.COM (Vaso Bovan) writes:
#The bel is of rather recent vintage, 1923 [ A Dictionary of Scientific Units,
#4th Ed., Chapman & Hall, 1980]. This source contains the statement that "in
#continental Europe, the neper is used instead of the bel." Is this true,
#European readers ?
Nobody I knew of used neper. Isn't it supposed to pertain to RF levels?
Nobody used bels either. But everybody used decibels about sound levels.
And volume was something we measured in cubic meter.
Which leads to the next interesting question: Why is sound level or
sound level control called 'volume?'cees@maestro.htsa.aha.nl (Cees Keyer) (11/01/89)
In article <1038@root44.co.uk> jgh@root44.UUCP (Jeremy G Harris) writes: +>In article <30339@buckaroo.mips.COM> vaso@mips.COM (Vaso Bovan) writes: +>>The bel is of rather recent vintage, 1923 [ A Dictionary of Scientific Units, +>>4th Ed., Chapman & Hall, 1980]. This source contains the statement that "in +>>continental Europe, the neper is used instead of the bel." In Europe we use the bell instead of the neper. The bell is a measure for good things but is a large unit hence picobello :-). +> +>Obsolete, I think. A faint memory tells me that the neper is natural-log based +>rather than log-base-10 based. Never seen it used. +>-- The neper is used in transmision technology. -- DISCLAIMER: I am not insane, I am a plane. pjew! Cees Keyer, Algemene Hogeschool Amsterdam. | fax: (+31) 20-443215 department of electrical engineering. | phone (+31) 20-429333 Email: cees@maestro.htsa.aha.nl cees@tamtam.htsa.aha.nl Snail: AHA-TMF, Europaboulevard 23, 1079 PC Amsterdam, The Netherlands.
jgd@rsiatl.UUCP (John G. De Armond) (11/02/89)
In article <2917@psivax.UUCP> torkil@psivax.UUCP (Torkil Hammer) writes: >Nobody used bels either. But everybody used decibels about sound levels. >And volume was something we measured in cubic meter. >Which leads to the next interesting question: Why is sound level or >sound level control called 'volume?' That's easy. The control varies how many cubic feet of sound get produced by the speakers. Didn't you know that the standard bell (of the church variety) held about 1 cubic foot? Or that the home version was about a tenth as spaceous, ergo the decibel? Of course, if you have a hundred or so of these decibels, the great pressure of the large volume of sound, especially the higher density sounds, can cause damage such as cracked plaster, damaged ear drums and so on. Oh yeah, .... :-) John -- John De Armond, WD4OQC | Manual? ... What manual ?!? Radiation Systems, Inc. Atlanta, GA | This is Unix, My son, You emory!stiatl!rsiatl!jgd **I am the NRA** | just GOTTA Know!!!