Please can anyone find for me the Gain?

Discussion in 'Analog & Mixed-Signal Design' started by student111111, Jul 26, 2016.

  1. student111111

    Thread Starter New Member

    Jul 26, 2016
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  2. BobTPH

    Active Member

    Jun 5, 2013
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    Please put the schematic in you post. I don't click on random links that might infect my computer.

    Bob
     
  3. student111111

    Thread Starter New Member

    Jul 26, 2016
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    Greetings
    I do understand that u might be suspicious and worried about your pc there is plenty of trojans around so for that how do you recommend me to upload the figure you would like it on Dropbox or via email or whatsapp Image or any other method kindly note that is is an urgent issue and I would like to find the gain of this circuit

    I attached the graph here if this is not enough or not a trustworhty issue let me know!
    Thank you in advance
    Ali
     
  4. benta

    Member

    Dec 7, 2015
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    I'd say a Kirchhoff node analysis is the way to go here.
    Apart from that, I'm not doing your homework for you.
     
  5. m zaid

    Member

    Jan 9, 2016
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    Sarcastic is rude. Don't talk like that to someone you just met and asking for help.
     
  6. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    You didn't ask for help. You asked someone to do the work for you.
     
  7. DickCappels

    Moderator

    Aug 21, 2008
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    Please upload your schematic using the "Upload" button.

    Who would ever design a circuit like that....?
     
  8. Bordodynov

    Active Member

    May 20, 2015
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    See
    Draft313.png
     
  9. DickCappels

    Moderator

    Aug 21, 2008
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    It looks like you have the correct, if we ignore mention of R4.
     
  10. hp1729

    Well-Known Member

    Nov 23, 2015
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    But that is not the original circuit. His non-inverting input is the output. Wouldn't it be the same voltage as the inverting input. Gain of 1.
     
  11. Bordodynov

    Active Member

    May 20, 2015
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    I am sorry/
    See new file
    Draft315.png
    Draft316.png
     
    Last edited: Jul 29, 2016
  12. hp1729

    Well-Known Member

    Nov 23, 2015
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  13. hp1729

    Well-Known Member

    Nov 23, 2015
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    Strictly a classroom question without practical application?
     
  14. Bordodynov

    Active Member

    May 20, 2015
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    Apparently you do not understand.
    Gain = Vout / Vin = V (out) / 1V = x.
    The question you have put wrong. Maximum transmission coefficients on the pseudo-resonance is 1 = 0db (at a frequency of 159Hz =1/(10k * 0.1u) / 2Pi. On the other frequencies ratio is less than 1. Carefully watch my pictures. I showed what is (analytically) transfer coefficient. I used complex number.
     
  15. hp1729

    Well-Known Member

    Nov 23, 2015
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    Certainly something for me to learn here. Math aside .. the output is connected to the non-inverting input. Shouldn't that follow the inverting input for a no gain condition? Frequency characteristics of the op amp not considered in my thoughts, of course.
    Given your formula, if we double the values of R3 and R4 we get a gain of -2. ??? It seems the output of the op amp would follow your math but the output of the circuit is not the output of the op amp.
    (edited to add ...)
    Or will the inverting input be at virtual ground and the output following that. Not no gain. no output???
    Or a current output like a Howland Current Pump?
     
    Last edited: Jul 29, 2016
  16. Bordodynov

    Active Member

    May 20, 2015
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    LTspice ==> Mag(Gain)=1 Phase=-180 ==> Gain=-1 (freq=159Hz)
    A formula I recheck. It seems I made a mistake somewhere.
     
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