Jan Panteltje writes:

On a sunny day (Sat, 02 Feb 2013 05:25:57 -0500) it happened Spehro Pefhany
wrote in
:

On Fri, 1 Feb 2013 16:55:24 -0000, the renowned "Ian Field"
wrote:



"Jan Panteltje" wrote in message
...
On a sunny day (Fri, 01 Feb 2013 13:17:42 GMT) it happened Jan Panteltje
wrote in :


OK, but that is actually an integrated circuit.
Just mis-labeled 'transistor'.
:-)

PS,
some of us here will remember RTL logic.
That was pretty much like that, but more transistors to make gates, and
output R too.
Integrated circuits.


My first job was component level fault finding on Olympia desk calculators,
they contained about 4 boards of DTL - a 5th board at the back was
critically sensitive MOS shift registers. The boards were about the same
area as S100, but wider & not so high, the front board had about a dozen
nixie tubes.

I must've just missed out on RTL by not all that long, it was only just
becoming scarce in component catalogues of the day.

When I was a kid RTL became very available in surplus surface-mount
packages (called "flat pack"). Probably some big military change-over.
DTL didn't seem to last long.

You could get cheap DTLand TTL chips here sold as 'bipack'.
Those were for example 7474 D flip flops with one defective flip flop in the package,
or a 7400 with one or more gates defective.
Once bought some of those, tested them, and marked the defective pins with
red marker.
Great for hobby projects :-)
Not so good if you made a PCB I guess :-)

Hey I remember those, in UK you could get bags (literally) of 7400 and
4000 series stuff, all of them test rejects. Many of them unmarked or
with some house code I think. As a kid I built a succession of "IC
Testers" , fixtures with LEDs and push buttons on each pin. Never
actually *did* much with them, it was more fun testing them. The CMOS
gates were cool, you could make a the outputs go on and off by waving
your hand near them.


Spacing was tight for attaching fly wires.. looks like it was
relatively coarse by today's standards- maybe 1.27mm pitch like
today's SOICs.


mm I have wire wrapped several designs with TTL.



--

John Devereux