Help Op amp circuit

Discussion in 'Homework Help' started by awesome2999, Apr 10, 2010.

  1. awesome2999

    Thread Starter New Member

    Apr 10, 2010
    7
    0
    Hi everybody,

    i have got a question about logarithmic amplifier.
    the operational amplifier is ideal and the diode current is given by the "real" diode equation = exp / − 1 . Assume = 2000Ω, = 10−16 A and = 0.0252 V.

    1-If the input voltage is = 1.5 + cos 2100 V, use MATLAB to plot versus for 0 ≤ ≤ 30 ms.

    2-The input voltage is now changed to = 5 + sin 2100 V, versus for 0 ≤ ≤ 30 ms.

    Use the small-signal model of the diode to predict the output voltage for the input voltages given in 1 and 2 .

    i'm not sure how to start analysis this cct
    i know the question will be
    Vout=-0.0252ln(Vin/IsR)

    [​IMG]
    many thanks
     
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