[sdiy] uA726, heated pairs (slightly OT)

[Peter Grenader]

OK, this is too weird.  I'm not sure if it's even related, but it is surely
a strange coincidence.

A while back someone turned me on to a deal from a guy who had 726's for a
very good price.  I got one and contacted him a couple of months later for
more, and he had sold all of them (something like 500 of them) for $200 a
crack to the US Government.

No bull.

To think,  all of those Buchla 258 clones blowing up over Baghdad. It makes
me want to scream!


metasonix wrote:

>>> ... but why the heck do you need a thermostated matched pair in a
>>> missile?  I really found that kind of bizarre.
>> They were part of all kinds of basic modules (multipliers, square roots
>> extractors, expo converters, etc) on analog computers, used in automatic
>> flght control.
> 
> And if you do some research on early missile development, you will find that
> large rockets didn't become really reliable (and the US space program
> didn't get started) until mostly solid-state control and telemetry circuits
> were developed. 
> Before that, they tried to use subminiature tubes, with questionable results
> 
> Raytheon actually made a bizarre tube that performed square-law
> conversion. Yes, for missile guidance analog computers.
> And National Union made analog telemetry commutator tubes.
> Literally a big (fragile) glass tube doing the function of a 4051 analog mux.
> There were also CRT-pickup dual tubes used to trace over a clear plastic
> graph and generate a control voltage, in kinescope fashion.
> You will see NONE of this stuff in old tube manuals.
> 
> A major reason why ceramic planar tubes were developed, and then
> semiconductors, was to make missile guidance systems more
> reliable. Computers didn't count as a market until transistors dropped
> below $1 wholesale price, in 1958.
> 
> Consumer electronics didn't count for much in technological development.
> Tube TV sets were still being made by Sylvania until 1976.
> And in Russia until 1995. The only place transistors made a real
> difference was in portable radios, until 1970 or so.
> 
> 
> 
> uncle eric
> metasonix.com
>