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Idea for a simple electronics project

Discussion in 'Electronic Basics' started by [email protected], Jan 14, 2006.

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  1. Guest

    Hi peaple,

    I have to do a simple electronic project for Elec. Eng. Lab. course in
    my college. But I have not any idea what to do. We still haven't study
    active components, just only DC and AC RLC circuits. This project has
    to include about 20 components. Using of active components is allowable
    but I wouldn't like to use something what I don't undestand how does it
    work,maximum I agree to be used is LED. I surfed the Internet, found a
    huge collection of circuits,ideas etc., but it is not for my knowledge
    level yet. Can anyone help me with the above, please ?

    Thank you in advance.
  2. Just about any functional block that uses more than 4 or 5 Rs, Cs, and/or Ls
    and no active components is either so sensitive to component values that you
    won't get it to work, or attenuates the signal so much that it can't do
    anything interesting.

    So, you might consider circuits that switch between several different
    functional blocks.

    For instance, you could make a selectable audio filter, that let you switch
    between RC or RLC passive highpass, lowpass, bandpass, and notch filters;
    you could then feed some music through it and listen to the output, and hear
    the effect.

    I guess if you include LEDs and diodes, then you can also do a few very
    simple logic operations. For instance, you could make an LED turn on if any
    "M" (or more) out of "N" possible inputs are shorted to ground. I don't
    know how interesting that is, though.

    Surely this is an entry-level class, so surely there are some advanced
    students who have already completed this class. How about asking some of
    them what projects they worked on?
  3. <snippety>

    You have many resources open to you, including fellow students who
    may be at a higher skill level and your college library.

    I will add that I question the value of the assignment if your
    instructor is specifying that many components for an (apparently)
    beginner-level course. Also, as others have pointed out, that many R, L,
    and/or C components with no actives is not going to be able to do
    anything truly useful unless you're doing advanced passive filter

    Another resource that you may be overlooking is whatever
    population of amateur ('ham') radio operators is in your part of the
    world. If you can find a club in your area, it could prove to be a
    viable technical resource. Granted, I have no clue what the hamateur
    environment in Israel is like, but it could be worth a shot.

    Happy hunting.

    Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute.
    (Known to some as Bruce Lane, ARS KC7GR,
    kyrrin (a/t) bluefeathertech[d=o=t]calm --
    "If Salvador Dali had owned a computer, would it have been equipped
    with surreal ports?"
  4. Guest

    My recommendation is that of between all the projects
    that you find, choose the easiest of all.
    Do not try to choose something very complicated, simply
    choose one that you can really make without great problems.
  5. Blake

    Blake Guest

    Well, these requirements seem to be shouting "Crystal Radio". It's just an
    LC filter with a detector diode and a pair of headphones. The crystal
    (diode) is an active component but it's only just one, and an
    easy-to-understand one.

    Your biggest problem would be getting the component count up to 20. A
    triple-tuned rf stage does nicely, as shown in this write-up.
  6. Guest

    Dear Dr. Anton and others who tried to help me,

    Thank you for your efforts to help me. Unfortunately me and other
    students in my college still have the problem with that task, except
    those students who already work in electronics area. This requirement
    of our instructor is stupid, since I see it is impossible to construct
    any project, based on R,L,C elements only. You're right.

    Best Regards
  7. Without an AC or DC power source, or some means to detect or use the output,
    what is the point of any circuit <G>?

    However, assuming you can add more than passive components, a great place to
    start is - and I suspect you can buy this magazine
    even in Italy. Possibly your library has copies.

    See also

  8. Mike

    Mike Guest

    A small Tesla coil maybe?
    No active components and a rather dramatic output.
    It'll take serveral series/parallel caps to get the parts count up.
  9. Seeing as that the requirement to have at least 20 components is quite
    silly, make a silly circuit in return!
    Make 10 RC filter circuits, each with a different resistor value.
    Connect the inputs together, fed in a signal and then measure the
    output with an AC voltmeter or CRO and plot a graph of the results and
    compare with the theory.
    Give it a fancy name like "filter response compliance verification
    test" or something!

    Dave :)
  10. Well now, I wouldn't go that far. ;-) The diode is a semiconductor,
    but AIUI it is still a passive component since it cannot create gain in
    this application. :) I would say that it can't create gain in any
    application, but someone would probably demonstrate that it can. ;-D

    I do think the crystal set is a good idea though. It's easy to make
    work then the OP can spend the rest of his/her time adding active
    circuitry to improve its performance.
  11. Jasen Betts

    Jasen Betts Guest

    how about a graphic equaliser?

    4 or 5 bands should get your parts count up there.

  12. redbelly

    redbelly Guest

    Perhaps part of the project (whatever it turns out to be) could be an
    AC-to-DC converter, just to help get the component-count up. You could
    get more details by googling or looking in electronics books, but it
    would include:

    1 transformer, to convert line voltage to non-lethal levels (eg. 9
    4 diodes + 1 capacitor, for a full-wave rectifier
    1 voltage regulator + 2 filter capacitors, for steadier DC voltage.

    That's 9 components, now you need to come up with a DC circuit using 11
    components, about 1/2 of the original requirement.

  13. Blake

    Blake Guest

    Fair enough.

    I hear various definitions of active and passive components that seem to
    allow the detector diode to edge into either category. I think of an active
    component as one that is powered. Detector diodes are often biased to
    improve sensitivity, as was the one in the link I provided. That's why I
    classified it as an active device, even though it has no gain.

    Other types of diodes, impatts and tunnel diodes for example, can amplify
    signals. But of course we're not talking about those sorts of diode for a
    crystal radio.
  14. JeffM

    JeffM Guest

    This requirement of our instructor is stupid,
    Well, it IS impossible to construct an electronic circuit from only
    The difference between ELECTRONICS and ELECTRICITY
    is **ACTIVE DEVICES**.

    I like Walter's idea (Jasen's is quasi-similar).
    An old receiver with a Preamp Output and an Audio Input
    will make his idea duck soup[1] to demonstrate.
    Just make a network that is complicated enough
    to get up to the required parts count.
    David's idea is along the same lines,
    but even a non-techie will immediately grasp Walter's.
    [1] Very easy.
  15. Tim Williams

    Tim Williams Guest

    *Cough* Alternate plasma/no plasma on the spark gap sounds (and behaves)
    "active" in my opinion. ;-)

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