The circuit in Figure P7.48 is a hybrid- \(\pi\) equivalent circuit including the resistance \(r_{b}\).

(a) Derive the expression for the voltage gain transfer function \(A_{v}(s)=V_{o}(s) / V_{i}(s)\).

(b) If the transistor is biased at \(I_{C Q}=1 \mathrm{~mA}\), and if \(R_{L}=4 \mathrm{k} \Omega\) and \(\beta_{o}=100\), determine the midband voltage gain for (i) \(r_{b}=\) \(100 \Omega\) and (ii) \(r_{b}=500 \Omega\).

(c) For \(C_{1}=2.2 \mathrm{pF}\), determine the \(-3 \mathrm{~dB}\) frequency for (i) \(r_{b}=100 \Omega\) and (ii) \(r_{b}=500 \Omega\).

Transcribed Image Text:

Figure P7.48 www ww 8mVx RL