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  1. #1
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    calculate output impedance

    How to calculate the output impedance of amp with feedback when I want to calculate the openloop gain,thank you.

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  2. #2
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    how to calculate rc impedance

    210k resistance is your load?



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  3. #3
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    how to calculate output impedance op amp

    To Calculate:
    Let Ro = Open Loop Op Amp output impedance
    . Ao = Open loop op amp gain
    . Ac = Closed loop op amp gain
    . Rc = Closed loop op amp output impedance
    . Then:
    Rc = Ro(Ac/Ao)

    To measure, using the circuit that you propose;
    Let Vs = the "battery" voltage
    . Rc = Closed loop op amp output impedance
    . Rl = the load resistor (the 210K resistor that you show)
    1) Remove the load and battery
    2) Tweek the input so that the output voltage = exactly 0
    3) Re-apply the load, Vs
    4) Adjust the load (Rl) so that the output current is just below the
    . op amp rated load current for linear operation.
    Let Vo = the output voltage under these conditions.
    . Then:
    Rc = VoRl / (Vs - Vo)
    .
    The problem with this method is that Vo is very small, making accurate measurements difficult.
    .
    Regards,
    Jon



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  4. #4
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    caluclate output impedance operational amplifiers

    I think not only taking account of RL but also the resistance in the feedback net, right?



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