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Some general questions on learning electronics

Discussion in 'Electronic Basics' started by zalzon, Aug 4, 2003.

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  1. zalzon

    zalzon Guest

    I've always dreamt of inventing little gadgets & gizmos so
    one day, I started on an introductory electronics course (found on
    twysted-pair's website).

    Though I am determined, learning electronics is a little tougher than
    I expected.

    Now for the questions :

    1) Do you think the course I am learning gives me most if not all of
    what i need so far as analog electronics goes? Please take a look at
    the lesson topics :

    Do those topics cover all the essentials of analog electronics or is
    there another motherload of theory to absorb once I'm done with that.

    2) Do electronic engineers building say robots or cell phones use
    mostly analog or mostly digital electronic components in their gizmos?
    Does industry require electronic technicians/engineers with mostly
    analog or digital skills?

    3) Are there a certain number of important circuits which are commonly
    used in design of electronic circuits. Could you list them.

    4) When you look at a complex schematic, where does your eye look
    first? How do you analyse what is happening in the middle of the
    circuit for instance? Do you start at the power supply and move to
    the middle. Do you "chase the flow of electrons" in the circuit to
    understand what's going on at every point. Or do u take a nebulous
    view of it? Or do u view it in blocks and say 'here's the common
    emitter amplifier', 'here's the full wave bridge rectifier', here's
    the whatever..etc. ?

    5) I often see current being represented as a flow from + to - and the
    direction of the arrow is usually that way in text books. Whereas I
    tend to think of current as a flow of electrons from the ground up to
    the positive. Is this wrong?

    6) Are microchips, fpga, asics..etc all based on the same principles
    of analog electronics. I know there are transistors on a microchip
    but are the principle of operations the same as how I"m learning it?

    I have more questions but I'll stop here.

    Thanks, i hope these are not silly questions.
  2. I am out of the field pretty much now, but here is a list of sites
    that, at least at a cursory glance, satisfied me. Although they aren't
    in any particular order, note the first one. :)

  3. It doesn't look at all complete. All the way through the last
    one looks more like the first few chapters of a good book on the
    subject. It *may* be as complete as Heathkit's old 4-volume
    coverage, but I can't tell since I can't look at the for-fee
    These days, I doubt you can perform electronics engineer work
    without knowledge in both -- mixed signal design is increasingly
    difficult to avoid. And to remain competitive, you may need to
    find the right balance between these two. Cell phones, in fact,
    are an excellent example of this.
    I don't think it's possible to list the important circuits. But
    I'm no expert anyway, so I'd probably miss a great many of them.
    Schematics are, generally, supposed to be laid out to aid your
    understanding. But quite often, I think, they aren't. Instead,
    they will often endeavor to highlight the mechanical connections
    between components, for example. Or something else, such as
    just plain slippiness or else tracings from a PCB layout without
    bothering to reshape it for good reading, later.

    So the first thing I usually do, if it isn't already dead simple
    and can be read easily as it stands, is to see if they've done
    the more basic things in drawing the schematic. Some things are
    just plain useful in helping to unwind a Gordian Knot, even when
    you don't understand it. For example, making electron flow go
    from bottom to top and re-arranging the components to achieve
    this. That can be done without really knowing what the circuit
    does. Another is to arrange signal flow (or what you imagine as
    signal flow) to go left to right (and maybe right to left, if it
    is feedback.) Actually, these two go hand in hand, since as you
    get the electron flow worked out, the signal flow will mostly
    straighten itself out, as well. Or you'll have a lot more clues
    about that. Once that is done, you are miles ahead.

    You also need to be familiar with basic patterns. These may be
    things like "wilson mirrors" or "cascodes" or the various
    common-emitter/collector/base configurations for transistors.
    Or just your basic RC filter. Or a simple peak detector with a
    diode and cap. Stuff like that. Just get as familiar as
    possible with a lot of simple combinations of small numbers of

    Books help a lot, here. I suppose tutorials, too. They can put
    various common arrangements in front of you so that you develop
    a familiarity with these patterns. A highly skilled electronics
    engineer will have a very large repertoire of these design
    patterns in their heads and will be able to pick them out in
    even poorly drawn schematics -- because they've "been there,
    done that" so many times.

    Also, don't just learn theory. Get a power supply. Get a volt
    meter. Get some tools and parts and build some of these things
    and then play with them. Start with something in a book or
    diagram and then Vary stuff they didn't tell you about and see
    what happens. Experiment, ask yourself "why," and then work at
    'understanding' the reasons.
    Just be consistent. It's almost never an issue, except in
    semiconductors where there is a difference between electron flow
    and hole motion, majority and minority carriers, for example.
    As far as I'm aware, almost always. At low enough levels, there
    are quantum effects (such as the fact that photons are bosons
    and have a "clumping effect" noticeable at very low levels.)
    But at almost any reasonable level, it's all analog stuff. If
    you look at the schmidt trigger input circuit, say a simple one
    with two transistors, you'll see how analog is used with
    positive feedback to make things appear rather digital.
    'Excessively' high gain is another way to get there, too.

    Bear in mind that I'm only a hobbyist, though. I've nothing
    like the experience of many here or elsewhere. So this is just
    my little slice of the world and it's not much of a slice, at

    Technician Tonny likes this.
  4. Gerry Ashton

    Gerry Ashton Guest

    I'll comment on some of your questions.

    Everything seems to be moving more and more towards digital, although,
    the higher the frequency and the higher the power, the more you still see
    analog. Also, even when working with digital circuits, you may need
    analog skills and measurements to see if the digital circuit is working

    I look at it at as high a level as I can. I just think about the general
    of a part of the schematic if I can, I think of it as blocks (common emitter
    amplifier) when I need to, and finally look at the details of the voltages
    and currents after I have narrowed things down to the area of interest.
    Both ways of thinking are useful; be prepared to think in different ways.
    It often takes less space to build transistors than resistors or capacitors,
    so many solutions will have a greater number of transistors than in a
    discrete circuit. Also, transistors, especially bipolar transistors, tend to
    be well-matched when they are close to each other on a chip, so some
    circuits depend on this match; the same circuit might not work with
    two discrete transistors pulled at random from a parts bin.

    Gerry Ashton
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