The closed-loop characteristics of the feedbackbias confi guration of Fig. 7.34a can be improved appreciably if we buffer the amplifi er’s output with an emitter follower to reduce loading by the...

The closed-loop characteristics of the feedbackbias confi guration of Fig. 7.34a can be improved appreciably if we buffer the amplifi er’s output with an emitter follower to reduce loading by the feedback network. In Fig. P7.23, Q1 is the amplifi er proper and Q2 is the buffer. To appreciate the improvement quantitatively, let us use the same component values of Example 7.15b (RB 5 5.0 kV and RC 5 10 kV). Moreover, assume both BJTs have gm 5 1y(25 V), 5 5 kV, and ro 5 100 kV. Estimate Ri , Ro, and the unloaded gain Aoc 5 voyii . Compare with Example 7.15b, and comment.