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From: Chuck Simmons
Organization: You jest.
X-Mailer: Mozilla 4.61 [en] (X11; U; Linux 2.0.33 i586)
Subject: Re: Historical question: negative feedback and the op amp
References: <email@example.com> <3DD3A787.499E9DDB@webaccess.net>
Date: Fri, 15 Nov 2002 01:36:40 GMT
NNTP-Posting-Date: Thu, 14 Nov 2002 17:36:40 PST
> "Chuck Simmons" wrote in message
> > Mike wrote:
> > >
> > > "Walt Jung" <firstname.lastname@example.org> wrote in message
> > > news:email@example.com...
> > > > I recently researched this area in writing a historical
> > > > section of the ADI book, "Op Amp Applications", which is/was the focus
> > > > of a seminar series. See www.analog.com/seminar This book will be
> > > > available next week for anyone interested.
> > >
> > > Walt, this was exactly what I was looking for. In my book collection, I
> > > lots of radio and communications books from the pre-WWII period, but
> > > systems books don't appear until post-WWII, and most of those that I
> > > are from the second half of the 1950's. My suspicion has been that the
> > > op-amp was conceptually invented at the same time as control theory, but
> > > references are a little thin. You've filled in lots of missing area...
> > > thanks!
> > Control theory is ancient (going back to water clocks and such) but
> > stability criteria for feedback control systems were known in the second
> > half of the 19th century.
> Yes, I've come across references to stability criteria developed in the 19th
> century, but control theory as a separate discipline didn't really arrive
> until the WWII time frame. That's what I was thinking of (no slight to
> earlier researchers intended).
I sometimes wonder if control theory ever did truly become a separate
dicipline. A good many practitioners of it are like me and never made a
systematic study of the subject. Also, there tend to be a lot of people
who do not recognize feedback and control in non-electronic systems as
the sames as feedback and control in electronics. I can't see any
difference myself. This, I suppose, widens my view a bit.
I used to drum up partial funding for conferences in mathematics at the
University of Colorado at Colorado Springs. DEC was a good source of
funds in those days and I could argue my way to the liberation of a few
thousand from the bean counters (my boss helped also). One of them was a
four day conference on Ordinary Differential Equations and Control.
Bringing some loot to the party got me invitations to sit at the table
for organizers and sponsors at the opening and closing dinners. They sat
me next to the Dean of Engineering. The only reason I knew anyone in the
college of engineering was because the mathematics department had been
stupidly thrown into that college. The dean opened the conversation with
me by saying he thought the conference was worthless. I had been
introduced to him as an engineer from DEC. He had very seriously put his
foot in his mouth with me. I had a very hard time keeping my temper
through dinner. It slowly unfolded that he had an incredible NIH
attitude to engineering applicable work being done by "outsiders" who
did not hold his subject in reverence. He was an electrical engineer but
that didn't matter. It was his attitude that I didn't like. He clearly
had a very narrow view of control.
I recall that they seated me in the friendly camp for the closing
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons firstname.lastname@example.org
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