21 Dec
2007
21 Dec
'07
4:36 p.m.
Subject: Re: The 2N2/256-BSCP [was: Homebrew Drum Computer]
From: ard at p850ug1.demon.co.uk (Tony Duell)
Date: Fri, 21 Dec 2007 23:26:06 +0000 (GMT)
To: cctalk at classiccmp.org
I suspect the acronyms were invented by Elektor magazine over 30 eyars
ago. Although they're not still sued in said magazine, theu're handy :-)
There's also DUG and DUS (Diode, Universal, Germanium/Silcon).
>
> And any TUN or TUP will do, provided a device of comparable spec was
> reasonably available to hobbyists in the mid sixties. For my first
> efforts, at least, I'll be using the PN2222 in modern TO-92 plastic
Old TUNs and TUPs are in the 2n400 and 2n130x series of germainum computer
transistors. Next generation was the silicon 2n70x series and their
plastic cased counterparts.
PN2222 is a fair devices to use for that. Far better than early 60s devices
and being silicon far more stable too. Those should be easy to find for
under 4cents at the 100 peice level.
Do all
transsitors have to be of the same flavour, or could I use TUNs
and TUPs?
I'd never encountered the TUN & TUP TLAs before, so I looked them up:
Transistor, Universal NPN/PNP. Neat! Sure. I tened to use 2N3904/2N3906 to excess round
here. I don't think
they're quite the same spec as a TUN.TUP, but they're pretty universal in
their own right :-).
Good for both switching and RF too. Also the metal can TO18 parts the
2n2222A and 2n2905 when you need a higher Ic and of course the 2n2219
and 2n2907 in TO5 for the next power level up. All been around a long
time and dirt cheap.
>> packages. I'm not sure when the TO-92
package was introduced, but
> there were definitely plastic package transistors available then.
> SOTs are right out, though :)
The TI silicon TIS9x transistor series was popular.
Given that there's a limit on the number of
transistors, I don't see what
advantage using SOT23s would give you. OK, you could make it smaller,
maybe clock it faster. But the change in package wouldn't allow a totally
different architecture. So I don't see any particular reason to ban them,
since the same design could be built with compoents in 1960's packages.
The 2n3904/6 is about 10X or more faster than the 1960s germainium
parts and still better than late 60s parts. Most of the 1960s wer the
MADT germainium in it's odd metal (to39?) can or TO5 sized parts so
most devices like TO18 or TO92 will be smaller.
Allison
-tony