Chapter 11, Problem 11.6P

The diff-amp in Figure 11.3 of the text has parameters $V^{+}=+5\text{V}$ $V^{-}=-5\text{V},R_C=8\text{k}\Omega ,$ and $I_Q=0.5\text{mA}.$ The transistor parameters are $\beta =120,V_{BE}(\text{ on })=0.7\text{V},$ and $V_A=\infty .$ (a) Using Figure $11.3(\text{a}),$ determine the maximum common-mode input voltage $v_{cm}$ that can be applied such that the transistors $Q_1$ and $Q_2$ remain biased in the active region. (b) Using Figure $11.3(\text{b}),$ determine the change in $v_{C2}$ from its de value if $v_d=18\text{mV}.(\text{c})$ Repeat part (b) if $v_d=10\text{mV}$ .