[sdiy] Logic in cans?

[Roy J. Tellason]

On Saturday 03 December 2005 02:20 am, Aaron Lanterman wrote:
> So, I'm sorting through a bunch of IC's in can's there's some CA3018
> transistor arrays - and some other stuff that appear to be amplifiers of
> various sorts, and then there's a HEP580 and a HEP583, which are claimed
> to be (according to datasheet arcchive), 2 input nor and a single j-k
> flip flop, respective.
>
> Whoa. I've never seen logic in cans before... apparently it's RTL
> (resistor-transistor-logic).

I have,  you're just too young to remember this stuff.  :-)

HEP is a series of parts I haven't bumped into in ages,  I think it was 
Motorola that originally came out with them,  aimed at the hobbyist rather 
than the repair/replacement market,  and it eventually went away.

RTL is designed to operate off a +3.6V supply,  though it's not real critical,  
I've run it off 3V-6V with no problems.  A typical 2-input NOR gate is two 
transistors,  both emitters grounded,  both collectors tied together and to a 
load resistor (your output),  each base with a series resistor (your 2 
inputs).  The can and have been used in all sorts of ciruits in the hobby 
area,  the most popular part number to my recollection being the uL914, which 
was a dual 2-input NOR gate like I describe.  I remember seeing a _mixer_ 
built with some of those.   And yes,  you can bias them into linear operation 
like a lot of other gates.

This stuff was big in the surplus market in the early 1970s or so.  I may even 
have some data on it or even some magazine articles that refer to it 
someplace.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin