Chapter 8, Problem 8.8EP

A transformer−coupled emitter−follower amplifier is shown in Figure 8.30(a). The parameters are: $V_{CC}=18\text{V}$ , $V_{BE}(on)=0.7\text{V}$ , $\beta =100$ , $a=10$ , and $R_L=8\Omega$ . (a) Design $R_1$ and $R_2$ to deliver the maximum power to the load. The input resistance seen by the ${\upsilon }_i$ source is to be $1.5\text{k}\Omega$ . (b) If the peak amplitude of the emitter voltage ${\upsilon }_E$ is limited to $0.9V_{CC}$ , and the peak amplitude of the emitter current $i_E$ is limited to $0.9I_{CQ}$ , determine the maximum amplitude of the output signal voltage, and the average power delivered to the load. (Ans. (a) $R_1=26.4\text{k}\Omega$ , $R_2=1.62\text{k}\Omega$ (b) $V_p=\text{1}\text{.62V}$ , $I_p=203\text{mA}$ , ${\bar{P}}_L=0.164\text{W}$ )