Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
References: <3DC282F0.email@example.com> <3DC2E327.firstname.lastname@example.org> <3DC3B8B8.email@example.com>
Subject: Re: how to master electronics, use of transistor, op amp...?
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Date: Sat, 2 Nov 2002 13:39:42 -0000
NNTP-Posting-Date: Sat, 02 Nov 2002 13:39:45 GMT
"Wafer" wrote in message
> Winfield Hill wrote:
> > Winfield wrote...
> >>Wafer wrote...
> >>> Please don't confuse skill with talent. Skill is acquired over
> >>>and involves much work and effort, while talent is there from the
> >>>beginning. However, lets not get tied up with semantics. I suppose
> >>>should have also pointed out my obsession with electronics. ...
> >>> [ snip ]
> >>> I would have to say that since Stephen William Hawking concerns
> >>>himself with theoretical physics and such, he may not be an
> >>>example of someone who would (or could) design an electronic
> >>>his head. Besides, it's not a matter of mathematics, or some
> >>>number of calculations. Rather it is something which I actually
> >>>difficult to put into words. I just do it. ...
> >>I find it difficult to design electronic circuits without extensive
> >>calculations, maybe not always written entirely on paper, but either
> >>performed in my head or using an ever-present pocket calculator, and
> >>with the results appearing on paper in one growing schematic
> >>or in a set of drawings representing different possible approaches.
> >>So, it's very hard for me to comprehend designing viable circuits
> >>without any schematic at all, either on paper or in computer file.
> >>Perhaps you'd like to try your hand at a design I'm completing now,
> >>a quiet transresistance preamp (current-to-voltage) that presents
> >>5pA current steps as 0.5V voltage-step outputs with a response time
> >>of 10us or better, with 100pF node capacitance. We'll have to also
> >>assume you already know the component's parasitic properties to make
> >>the appropriate selections and modify the design accordingly, right?
> >>If you quickly finish the design, you'll have time to design a test
> >>fixture to verify its impressive performance.
> >>To my mind this type of relatively-simple design cannot be achieved
> >>entirely in one's head, so it should be a good test for your skill.
> >>Remember, be honest now, no paper or computer allowed for this test.
> >> :-)
> > Oh, wafer, a few other circuit specs for this test. My circuit has
> > only two 8-pin ICs, makes measurements to 10fA without requiring
> > adjustments or calibrations, and drives a 50-foot cable. The two
> > are inexpensive parts that have been available for several years.
> Well, this sounds like an interesting little circuit. I actually
> don't usually approach a design from this prospective either. Again,
> self taught, and although it has obvious advantages to me, it
> means that my approach is to solve a particular need. What this
> requires is some understanding of the purpose of the circuit, not in
> turms of specs on paper, but in the real world application. Something
> like: here is a signal that need to get through a 50FT. cable with no
> more than so much loss. The signal can't see an impedance of less than
> x, and must arrive at the other end with as little distortion as
> possible, etc, etc.
The reality is, is that without a spec, you don't really have *design*.
> You see, I simply skip most of the calculations and just put
> together something that would probably have at least fair performance,
> then tweak the thing as needed.
>In the case of your circuit
> requirements, I can see that simply using a standard breadboard would
> screw up the whole thing. Stray capacitances alone would see to that.
> In any case, this entire discussion is not about my skill, talent,
> or anything else. It's not about any one person at all. The thread was
> started by someone asking how one goes about "mastering electronics",
> and asked for others to share experiences. That's what I did, and if I
> knew it would turn into a contest, I would not have responded as I
First, learn to reply at the end of the post, not the top.!!!!!!
The issue here, is that the description of how you claim to "design"
circuits goes against, I would say, 99% of what professional design
engineers actually do. With all due respect, its not really believable.
That's why the flack. You've got to accept that there are quite a few
here who have degrees *and* have many, many, years experience, and know
how things are usually done in commercial companies that you cant
bullshit with. If you claim things that are *known* to be dubious, you
going to get hit on.
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.