20 Dec
2007
20 Dec
'07
3:09 p.m.
Thu Dec 20, 2007 at 14:50 Tony Duell said:
Yes. Encouraged, even.
I'd never encountered the TUN & TUP TLAs before, so I looked them up:
Transistor, Universal NPN/PNP. Neat!
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
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 :)
I recall seeing a few two-layer boards in hobbyist electronics
magazines from the '60s. Certainly you can make multilayer boards
out of single-side boards, as long as you don't need to make many
connections to the inner layers.
Maybe it's an Australian thing. Being an ex-pat Yank in Oz, saying
"boot" instead of "trunk" still doesn't come naturally to me, even
after more than a year here. Saloon car, though, sounds like a sure
way to get a drunk driving ticket :)
-Bobby
...
1) To build a complete functional computer, including memory,
Are things like core-on-a-rope ROM allowrd? using no more than 256 2N2222-ish transistors
(plus scads of diodes,
resistors, etc.).
Do all transsitors have to be of the same flavour, or could I use TUNs
and TUPs? I think I'd start by reading the schematics of the
HP9100. It contains
more transistors than that, but it's still amazingly simple.
Anyway, the flip-flops in that machine were JKs, using 4 transistors
each. ...
I'll check that out. Thanks.
2) Use
no ICs or other parts that wouldn't have been available
to hobbyists ca. 1965.
So that preumably means a multi-layer-PCB acting as an
inductively-coupled ROM is out. Rats! 3) Must
be transportable in the boot of a mid-size sedan (i.e.
Totally OT, but I find 'boot of a sedan' a somewhat odd expession.
'Trunk
of a sedan' or 'boot of a saloon car' would seem more natural. 
20 Dec
20 Dec
7:08 p.m.
Robert Nansel wrote:
Thu Dec 20, 2007 at 14:50 Tony Duell said:
Another approach to discrete flip-flops can be seen at:
http://www.cs.ubc.ca/~hilpert/eec/misc/CasioAL1000Tech/electronics.html
The stacking of multiple inputs into the basic FF structure was another
technique from the discrete days. Helps reduce the amount of gating (and hence
transistors) required, for instance when making a parallel loaded shift
register or counter, although they were lots of other novel uses. (Some
aspects of logic design were narrowed with the introduction of ICs for the sake
of standardizing on elements that would fit in packages with limited connections.)
Anyway, the flip-flops in that machine were JKs,
using 4 transistors
each. ...
I'll check that out. Thanks. 
21 Dec
21 Dec
3:26 p.m.
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!
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
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 :-).
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 :)
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.
-tony
6:30 p.m.
On Dec 21, 2007, at 6:26 PM, Tony Duell wrote:
It'd be easier to assemble.
-Dave
--
Dave McGuire
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007
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 :)
Given that there's a limit on the number of transistors, I don't
see what
advantage using SOT23s would give you.
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ard＠p850ug1.demon.co.uk -
bnansel＠bigpond.net.au -
hilpert＠cs.ubc.ca -
mcguire＠neurotica.com