(Solved): (a) General Structure (b) Finding the A Circuit and (i) The A rimuit is Vi for each, t ...

(a) General Structure (b) Finding the $A$ Circuit and $?$ (i) The A rimuit is $V_i$ for each, together with the values of all the elements in the equivalent circuits. 11.34 The formulas for $R_{if}$ and $R_{of}$ in Eqs. (11.22) and (11.25), respectively, also apply for the case in which $A$ is a function of frequency. In this case, the resulting impedances $Z_{if}$ and $Z_{of}$ will be functions of frequency. Consider the case of a series-shunt amplifier that has an input resistance $R_i$, an output resistance $R_o$, and open-loop gain $A=$ $A_0/\left[1+\left(s/{?}_H\right)\right]$, and a feedback factor $?$ that is independent of frequency. Find $Z_{if}$ and $Z_{of}$ and give an equivalent circuit (ii) $?$ is obtained from ${??\frac{V_f}{I_o}?}_{I_1=0}$ (c) Gain, Input, and Output Resistance - Use the formulas in Fig. 11.21 to find ${A_f?}_{\text{ideal }},A_f,R_{if}$, and $R_{ef}$. - $R_{\mathrm{in}}$ and $R_{\mathrm{cut}}$ can then be found from $\begin{array}{c}{R}_{\mathrm{in}}=R_{if}?R_s\\ R_{\text{out }}=R_{ef}?R_L\end{array}$