[sdiy] Multipliers, was: Wavetable info

[Magnus Danielson]

From: Ingo Debus <debus at cityweb.de>
Subject: Re: [sdiy] Multipliers, was: Wavetable info
Date: Sat, 3 Jan 2004 16:39:46 +0100
Message-ID: <0F26971C-3E03-11D8-8ABF-000A9571C136 at cityweb.de>

> 
> Am Samstag, 03.01.04 um 08:29 Uhr schrieb KA4HJH:
> 
> >>>
> >>> Whilst true I have always thought that this does make for some
> >>> confusion. I think K is the only multiplier over 1 that exists in the
> >>> lower case. G, M and T being the most common others. Also annoying 
> >>> for
> >>> the unwary, the kg is a base unit and not the gramme.
> >>
> >> Yes, this IS an annoying detail and inconsistency. By the time that 
> >> things
> >> where put into a even more structured order a few things where to 
> >> late to fix.
> >> However, this inconsistency is well documented and the appropriate 
> >> format is
> >> international standard.
> >
> > Just glancing over the document Magnus sent me I see that hecto and 
> > deca
> > are lowercase. Not that I use them very often...
> >
> 
> Lowercase d is for Deca (10x multiplier)? Isn't that already used for 
> deci (0.1x multiplier), as in dB?

You are correct in that something is fishy, and yes, 'd' is used for deci,
the 0,1x multiplier. Deca is the only prefix using two leters, namely 'da'.
------------------------------
Y	yotta	10^24
Z	zetta	10^21
E	exa	10^18
P	peta	10^15
T	tera	10^12
G	giga	10^9
M	mega	10^6
k	kilo	10^3
h	hecto	10^2
da	deca	10
d	deci	10^-1
c	centi	10^-2
m	mili	10^-3
u	micro	10^-6
n	nano	10^-9
p	pico	10^-12
f	femto	10^-15
a	atto	10^-18
z	zepto	10^-21
y	yocto	10^-24

You _never_ combine prefixes, such as 1 mmF (which should be 1 pF) or 1ukg
(which should be 1mg, despite that 1 kg is a "base unit").

Also, you _never_ let the number before the prefix or the unprefixed number
be below 1 or above (or equal) 1000. I.e. 0,1 uF should be written 100 nF.

For instance, if you is going to be picky, you should not write 0,1 dB but
rather 1 cB since Bel is the unit (with B as symbol). Good gear can report in
mB steps but great gear is down to 100 uB or even 10 uB. But most people think
of dB as the base unit and for most cases I think it is the most practical, so
there is where I tend to think some abuse of the rules to be understandable.

Cheers,
Magnus