Solve problem 4.112 in the text with $R_C = 2.2 \text{ k}\Omega$. Find $R_{in}$ and the overall
gain $G \approx \frac{v_o}{v_{sig}}$ (i.e., $\frac{i_o}{i_i}$ is not required), assume $V_T = 25.3 \text{ mV}$ and $V_{BE} = 0.7 \text{ V}$.
Hint: Voltage division at $v_1$ is not valid because $I_B \ne 0$, use node voltage at $v_1$,
and you can also use the resistance reflection rule to show that $V_1 = 3.029 \text{ V}$.
4.112 For the common-emitter amplifier shown in
Fig. P4.112, let $V_{cc} = 9 \text{ V}$, $R_1 = 27 \text{ k}\Omega$, $R_2 = 15 \text{ k}\Omega$, $R_E = 1.2 \text{ k}\Omega$,
and $R_C = 2.2 \text{ k}\Omega$. The transistor has $\beta = 100$ and $V_A = 100 \text{ V}$.
Calculate the dc bias current $I_C$. If the amplifier operates
between a source for which $R_{sig} = 10 \text{ k}\Omega$ and a load of
$2 \text{ k}\Omega$, replace the transistor with its hybrid-$\pi$ model, and
find the values of $R_{in}$ and the overall voltage gain $v_o/v_{sig}$
and the current gain $i_o/i_i$.
