Figure 951
(A) for the Circuit in Fig $\left|V_{B E}\right|=0.7 \mathrm{~V}, \beta=\infty$

Essay

Figure 9.5.1
(a) For the circuit in Fig. 9.5.1 (refer to Figure above), assuming $\left|V_{B E}\right|=0.7 \mathrm{~V}, \beta=\infty$ (i.e., ignoring base currents), and $V_{A}=\infty$ (i.e., ignoring the Early effect), find the dc values of the labelled currents and voltages.
(b) If the bases of $Q_{6}$ and $Q_{7}$ are disconnected from ground and a differential input signal $v_{i d}$ is applied, find the differential gain if the output is taken between the two collectors.
(c) Repeat (b) for the differential amplifier $\left(Q_{11}, Q_{12}\right)$ .