Chapter 4, Problem 7P

Revisit the exact analysis of the inverting amplifier in Section 4.3.

(a) Find an expression for the voltage gain if $R_{in}\ne \infty ,R_{out}=0,$ and $A_o\ne \infty .$

(b) For $R_2=\text{27 kΩ}$ and $R_1=\text{3 kΩ,}$ plot the ration of the actual gain to the ideal gain for $A_o=\text{1000}$ and $\text{1 kΩ}\le R_{in}\le \text{100 kΩ}$.

(c) From your plot, does the ratio approach unity as $R_{in}$ increases or decreases?

(d) From your plot in (b), what is the minimum value of $R_{in}$ if the gain ratio is to be at least 0.98?