Re: Straight Forward Answers

Bart wrote:
"John Popelish" <jpopelish@xxxxxxxx> wrote in message
news:m4Sdnbgih80zd0PenZ2dnUVZ_tydnZ2d@xxxxxxxxxxxxxxx
Dennis Walter wrote:
I am not necessarily new to the hobby, i build a lot of pre-made
schematics and kits and such. Now i am looking for an electronics book
that tells me exactly what a component does, without going into all of
the math and extraneous material, i have enough books that do that. For
example, i want a book that says what a resistor does, and why you would
need that to be done, not necessarily how it does it, frankly i don't
care at this stage of my hobbying. Does that make sense? Most books or
tutorials i have read are not vague, but not written in the right context
for what i want.

I am pretty much self taught in electronics (before I got frustrated with
no one taking me seriously, and went back to school and got my degree), so
I think I know what you are talking about. So many text books go straight
for the descriptive equation, without taking a paragraph of 3 to try to
get you to imagine generally what a component is for and how it acts, in a
strictly conversational way. It is only after they wade into all the math
that the discussion of all the limitations, approximations and exceptions
where the equations do not apply, exactly, that you start to find out the
real "personality" of the various parts.

I taught electronics in the Army in the late 60's and picked up classes
full of people who had spent a half a year in practical training, and
still didn't feel comfortable thinking about resistors, transistors and
capacitors, even though they had passed many tests about them to get to
that point. I had to swing back through the basics, and try to get their
imaginations inside the parts, so they could look at a schematic and
imagine what was going on in the circuit, in a general way, for
troubleshooting purposes, as if they were a detective observing a room
full of interacting people, looking for clues of someone who was acting
out of character.

Unfortunately, I have not seen a text book that approaches things quite
that way. They all get into at least simple algebra before a chapter has
passed.

However, since this is the basics discussion group, there is no
electronics question too basic to be discussed. Ask a question about a
component and we will see if we can get inside your head and help you make
progress.



Does anyone else approach it as simple hydraulics or plumbing? I'm
somewhat teaching myself and I think in those terms, current being
the flow of water and voltage being water pressure.

See the insightful (and amusing) AN73 from Linear tech (available at
http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1142,C1114,P1134,D4162)




A resistor is
like a constrictive valve (bending a garden hose), a capacitor is like
a water tower, a diode is like a butterfly valve, a transistor is like a
faucet, etc. This type of thinking has its downfalls but has worked
enough to keep me from giving up. I'll read the chapter on transistors
in five different books and they all sound like rocket science. I'll finally
be in the company of someone with a working knowledge of transistors
and he can explain it in 10 minutes. Now why can't any of the expert
authors do that? This group has been VERY helpful to me several times,
members patient with my "dumb" questions and DO give straight answers.
A best seller would be a collaborative book authored by
sci.electronics.basics!
Bart

As to the original questions, I started on my own as well and had the
same issues - my first formal education in electronics being provided
at the Air Engineering school, Royal Navy. By then I had successfully
built many a hobby project, but it was quite an epiphany to see the
details of those parts I had used revealed properly. I would note,
however, that the explanation was by way not merely of the books issued
to us, but also the instructors taking the time to explain things in a
synonymous but functional way.

I have used many textbooks when teaching in the U.S. and I have yet to
find one designed for that purpose that truly explained components and
their properties in a non-technical way; yet a student is non-technical
until trained. That's why we had to do our own lesson guides (I still
have all of mine from a decade of teaching) to explain what the
textbook was actually speaking of.

That notwithstanding, there are some great guides that do explain
things in an intuitive way, although the best way is usually to talk to
someone who understands the component.

So - what is a resistor? It's a device that limits current (from one
perspective) or it is used to get a specific voltage across it's
terminals (from another perspective). It is both of these (and more).
The key is to understand what you are trying to achieve with the
component - and there ohm's law (or more properly the algebraic
statement that is a result of ohm's law as G.S.Ohm makes no mention of
the word resistance) is the device that makes it clear. Ignore the
units - rearrange the equaation and see what the result can be.

If you use some method of forcing a current somewhere and there is a
voltage across some device in that current path, it could easily be
called an equivalent resistor (and often is), even though there may be
no resistor in sight (at that part of the circuit, anyway).

Certainly I understand the desire to see a component described without
mathematics, and that is certainly useful. One should remember that
mathematics is a language - so describing things mathematically is
merely using a different language for the description, albeit a
language that can be somewhat arcane and non-intuitive ;)

Cheers

PeteS

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