Question

I am very confused as to how in initial equations for Ix in solutions they involve alpha. I think that Ix=gmVpi + (Rpi || Zpi)(-Vpi) if I think about the circuit as a small-signal circuit.

output mpedance the 11.48. Determine of the emitter follower depicted in Fig. 11.88, including C and other capaci tances. Sketch |Zourl as a function of fre- quency. Assume VA Vcc J RB Vina W Z out Figure 11.88