From: firstname.lastname@example.org (carltons)
Subject: Re: Historical question: negative feedback and the op amp
User-Agent: NewsWatcher-X 2.2.3b2
NNTP-Posting-Date: Wed, 13 Nov 2002 10:52:12 GMT
Date: Wed, 13 Nov 2002 10:52:12 GMT
In article , "Kevin Aylward"
> "Ban" wrote in message
> > "Mike" schrieb im Newsbeitrag
> > news:hBnA9.5273$XF5.email@example.com...
> > > Harold Black came up with his negative feedback theory in 1927, yet
> > > first op-amp wasn't invented until the 1950s.
> > >
> > > The op-amp seems like such a natural extension, once you know about
> > negative
> > > feedback. Why did it take so long for the op-amp to come along?
> > >
> > > -- Mike --
> > >
> > >
> > I do not think OpAmps come from the negative feedback idea, nearly
> > electronic circuit has been using feedback since the beginning of the
> > aera.
> > Rather the main idea is to combine a functional block in one unit,
> > requires some kind of integration.
> > Feedback in itself is more a cure for the unlinearity and other
> > shortcomings, nowadays it is no more needed,
> Jesus wept dude. How you can claim this is pretty amazing really.
> Feedback is most certainly a very usefull device, and imo, will *always*
> be used.
> > digital circuits work so
> > precise, they do not require feedback.
> But digital systems still use feedback, e.g. digital filters. Feedback
> control systems are indispensable, analog or digital based. Without a
> feedback temperature control system you would be dead.
> >Feedback is an antique thing,
> Sure is, so is the wheel.
> > wasts power and a *lot* of speed. It is just a crutch not something we
> > should cherish.
> I don't why you say this. Sure using analogue feedback has some
> negatives, but in most cases the advantages easily outweigh the
> disadvantages. Try and make a reliable fixed gain of 100 without
> feedback. This whole concept is not even debatable. Feedback is one of
> the most important pieces of science around.
> Kevin Aylward
> SuperSpice, a very affordable Mixed-Mode
> Windows Simulator with Schematic Capture,
I have a feeling that this thread will go off into the troposphere soon
due to conservation of misery. Feedback, linearity, etc. are all
important and will have to be thrown into the equation for a system.
Whether done with digital circuits or analogue you will arrive at the same
spot, no matter what. Whether you believe in analogue or digital, first
look at the equations. For instance, you don't get infinite slopes on the
side of a filter without the filter having infinite group delay and
passband ripple. The circuit implementation is unimportant. Ice cream
melts when it's 60 degrees celsius outside no matter how much you don't
want it to or how frozen you get it is before you put it out. Putting on
a happy face still gives you melted cream without the ice. God's laws
will always apply.
If this was a digital world, wouldn't we have no colours? Wouldn't we
have to goose step everywhere and either in a forward or backward
direction? ETC,ETC, :-)