Why is NS +12V regulator marked LM2940CT -12 ?
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From: N_Cook on 2 Apr 2010 11:26 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
From: nesesu on 2 Apr 2010 13:16 On Apr 2, 8:26 am, "N_Cook" <dive...(a)tcp.co.uk> 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 Uh, because that is the part number? The LM2940 family are low drop out POSITIVE regulators with the voltage shown as a suffix. Sure, the 79xx series were the negative regulators of the early series, but before that they had other numbers such as LM340 [I think]. Surely you cannot expect that they will avoid vaguely similar numbers to old devices just because someone MIGHT confuse them for a much older device numbering? It is also not National's fault that the dash and the minus sign happen to look very similar. Neil S.
From: Jeff Liebermann on 3 Apr 2010 02:48 On Fri, 2 Apr 2010 16:26:31 +0100, "N_Cook" <diverse(a)tcp.co.uk> 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 jeffl(a)cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
From: N_Cook on 3 Apr 2010 04:48 Jeff Liebermann <jeffl(a)cruzio.com> wrote in message news:dcodr557dgv0ueki1aob7idt0esai9jl3k(a)4ax.com... > On Fri, 2 Apr 2010 16:26:31 +0100, "N_Cook" <diverse(a)tcp.co.uk> 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 jeffl(a)cruzio.com > 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/
From: Mark Zenier on 3 Apr 2010 15:31
In article <hp6vbc$dur$1(a)news.eternal-september.org>, N_Cook <diverse(a)tcp.co.uk> wrote: >Jeff Liebermann <jeffl(a)cruzio.com> wrote in message >news:dcodr557dgv0ueki1aob7idt0esai9jl3k(a)4ax.com... >> On Fri, 2 Apr 2010 16:26:31 +0100, "N_Cook" <diverse(a)tcp.co.uk> 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 jeffl(a)cruzio.com >> 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/ Tradition. That's how they numbered both of their LM320 (negative) and LM340 (positive) parts. The 78xx and 79xx numbers were Fairchild, orginally. Mark Zenier mzenier(a)eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com) |