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.. the very best way to learn electronic design is with SPICE.
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If you know what you are doing and looking for, it saves some
calculations and/or bench time. It's pretty nice when you want to
verify what you already feel you understand to a fair degree but where
you want some key facets calculated for you that might take some
calculator time and where you might flub up at some step in the
complex chain. The Spice program will consistently do the same thing
for you, without accidentally moving a decimal point or picking up the
wrong substep worked earlier when moving forward later on.
It's like a good computer language compiler, in that way -- which
consistently produces equivalent code and flawlessly does the required
bookkeeping along the way. But if you don't know why the code was
written the way it was, the compiler isn't going to help you
understand it much better.
Theory is how we give meaning. Without theory, results are noise. So
running the output without having some theory in mind about the input
will only yield "so much noise." So knowing __why__ is important, I
think, when using Spice.
On the other hand, if you do understand _some_ things but are just a
little bit short of understanding enough of them -- then Spice can
yield just enough 'extra noise' in the results to push you towards the
rest of the understanding you may be missing. But what is important
then is that you already have much of it in mind and are close, but
just not yet grasping the fuller picture. Then some various runs in
Spice may force an "Ah, hah!" moment to gel some other theoretical
idea you'd read but hadn't yet put into context. But this doesn't
excuse avoiding studying theory as a prelude to using Spice.
To put what Spice is really, really good at into sharp relief, imagine
starting with learning the basic concepts -- voltage, current, and
resistance -- and Ohm's law. One quickly finds some easy facility
calculating values for DC voltage dividers and various simple
combinations. Then one is faced, someday, with a wye or delta or
wheatstone bridge or something still more complex with various voltage
sources and current sources and not easily yielding to early
knowledge. Facing up to that, one may learn to use Norton and
Thevenin equivalents with some facility and to gain some mastery of
branch current and/or mesh analysis and/or nodal analysis and the use
of matrix methods of simultaneous solutions. And even be able to work
out the right numbers every time. But it remains a bit of a pain,
too, and one wishes for a "solver" so as to avoid repeating the
details over and over, every time someone faces one of these. It's
not that you don't know the theory and it's not that you can't sit
down with paper and pencil and get useful results. It's just that the
details are many and bookkeeping a pain and it's really helpful to
just let some computer program do that part for you so that you can
focus on the larger design issues and not get mired in calculations
that take you away from more important considerations elsewhere. You
get more done in less time. But you still could do it, if you had to.
Spice is really good for that. But I don't see it replacing books on
theory.
Bob Masta nailed the basic idea, I think. One needs to learn how to
recognize blocks, how to design them, and how to adapt them. And even
then, Jan Panteltje's comment, "I only am [still only] familiar with a
subset," is squarely on the mark, too. One will never know every way
someone's knowledge and imagination has already been or might yet be
combined. One can only hope to know some. Experience seems to move
smarter folks from brazen confidence towards modest diffidence, so
that when asked how some designs might be done one will answer that
although they may know a few ways, they are sure many more exist which
were not only as yet unknown but almost unimaginable.
So maybe I'd rephrase your comment to, "a good way to focus more on
learning theory behind electronic design is to use SPICE to free you
of mundane calculations you already know something about while giving
you a few key answers to well-framed, knowledgeable questions."
That's my hobbyist view, anyway.
Jon
P.S.
Also, one thing Spice will NOT do is model reality. Just someone's
simplified model of it. So one still needs a lot of practical
knowledge and experience.
