Chapter 12, Problem 12.6EP

Consider the ideal shunt-series feedback amplifier in Figure 12.9. Assume that the source resistance is $R_S=\infty .$ (a) If $I_i=100\mu \text{A},I_{fb}=99\mu \text{A}$ , and $I_o=5\text{mA},$ determine $A_i,{\beta }_i,$ and $A_{if},$ including units. (b) Using the results of part (a), determine $R_{if}$ and $R_{of},$ for $R_i=5\text{k}\Omega$ and $R_o=4\text{k}\Omega .$ (Ans. (a) $A_i=$ $5000\text{A}/\text{A},{\beta }_i=0.0198\text{A}/\text{A},A_{if}=50\text{A}/\text{A}(\text{b})R_{if}=50\Omega ,R_{of}=400\text{k}\Omega )$