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
NS
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.
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:
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
NS
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 snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.