Question
5. [30%] Consider the op amp circuit shown below. R1=10 k[], R2=10 M, R3=10 k. Calculate the output noises (in V/Hz, square root of PSD) caused by el, e2, and in individually. Assume its input current noise in= 0.6 fA/Hz, independent on frequency. Ein O e1 www R₁ int R3 en R2 Noiseless Vno Op Amp Extra credit [10%] In the Norton model, the Johnson noise is inversely proportional to R. Will the noise become infinite when R approaches zero (e.g., short circuit?). Hint: add a load resistor R₁ (which is noiseless) then calculate the noise across R₁.
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