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Homework Help: Schmitt Trigger - Astable Mutivibrator Op-amps

  1. Feb 13, 2005 #1
    Who has the guts to do the problems given in the attached pdf file???

    I would like the folks competent to solve them to do Prb. 2 and 3.


    P.S. few weeks ago I had posted a file related to Op-amps but no fruitful help was gotten from this forum, eventhough I am posting this file.

    Hoping I get some good suggestions on these problems.

    Attached Files:

  2. jcsd
  3. Feb 13, 2005 #2
    Testing to see how many flies you can catch with vinegar?
  4. Feb 13, 2005 #3
    Well anyways, here's what I've thought

    In a general Schmitt Trigger figure:

    No resistor between Vin and the inverting input.
    It has a positive feedback along with a resistor R_3,
    The non-inverting input has constant 5VDC input which is V_ref, there is a resistor R_2 between V_ref souce and the non-inverting input.
    non-inverting input is also connected to the ground along with the resistor R_1.

    As in the fig. in the attached file of schmitt trigger...

    Now, V+ depends on V_out. When V_in < V_ref then V_out switches to V+saturation otherwise V-saturation.

    and V+(>) - V+(<) = (2 R_123 / 3)
    ( R_123 eq. of all the 3 resistors)

    The thing is what values of resistors shall I use?
    and whats the use of output current and the sink current?

    Attached Files:

  5. Feb 13, 2005 #4
    You can't have people do your homework for you! Go back to your teacher!
  6. Feb 13, 2005 #5
    if u can't post anything worthwhile then don't b.s. atleast.
  7. Feb 13, 2005 #6
    It *seems* like I am posting way too "advanced" stuff in here.
  8. Feb 14, 2005 #7


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  9. Feb 14, 2005 #8
    I did the same thing written in that post of yours except the way of finding input impedance.

    Anyways, for the problems I've posted over here - I already did them.
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