Jeff Liebermann wrote in message
...
On Fri, 2 Apr 2010 16:26:31 +0100, "N_Cook" wrote:

not printed as LM2940CT /12 say.
Any other awkward ones like that, hopefully to lodge in memory, or just a
NS
thing.
Not being familiar with that range the 9 in the type number triggers a
mental connection with 79 series negative regs

Because sometime, back in the days when electricity was being
discovered, decided to recycle the "hyphen" as a "minus" sign, under
the assumption that a "hyphen" would never be used in electronics, and
a "minus" would never be used in typography. The "hyphen" always
appends or prepends a letter, while the "minus" always prepends a
number. That actually worked quite well, until the invention of
electronic part numbers, causing problems as you have noticed. Sorry,
but I don't think lecturing the entire electronics industry on the
proper use of the "hyphen", "dash", and "minus" signs.

The best you can do is that if the symbol is preceded by a space, and
succeeded by a number, it's a minus sign as in -12volts. However, if
proceeded by a character, as in a part number, it's a hyphen. However,
that doesn't help when the laser markings word wrap the part number,
or someone arbitrarily adds a space to improve the appearance.

Note that the hyphen and dash are different:
http://en.wikipedia.org/wiki/Dash
http://en.wikipedia.org/wiki/Hyphen
http://en.wikipedia.org/wiki/Minus#Minus_sign

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


I later found a supplier listing of V regs by , indexed by maker name. Only
NS out of 6 makers adopted, still adopts, the use of the minus sign in some
positive device type numbers. The one that confused me is the wrap around
situation , but I still don't see why they could not have used underscore_
or slash/