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Common Source Aplifier - finding values of bypass capacitors

  1. Sep 18, 2006 #1
    I am new to this website. I am having troubles in designing a common source amplifier with a voltage gain, Av=26 dB (no bypass capacitor) and a gain of 40 DB (with a bypass capacitor) and a frequency of 100-1000HZ. Can anyone please guide me to calculate the value of the bypass capacitor? I searched everywhere for the methods of finding the capacitors values but still in vain. :frown: :confused:
    thank you very much for all your help.

  2. jcsd
  3. Sep 19, 2006 #2


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    Staff: Mentor

    Can you post a sketch of your circuit? Also, you list two different gains. What is the 40dB number representing?
  4. Sep 19, 2006 #3
    Dear berkeman,
    Thanks a lot for your reply. The 26 db is the gain when there is no bypass capacitor in the circuit while the 40 dB is the gain when there is a bypass capacitor in the circuit.
    Oh by the way, do you know how to use PSPICE or LTSPICE to generate the circuit? I am so sorry for sounding like such a poor computer engineer student. I am trying to learn how to use PSPICE or LTSPICE to generate the results.
    Thank you very much for your help. I really appreciate all the help given.

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