Equation (5.68) was derived under the assumption of an ideal input voltage buffer. A real-life buffer will exhibit a small output resistance Rn, as shown in Fig. P5.38. (a) Show that Eq. (5.68) still...

Equation (5.68) was derived under the assumption of an ideal input voltage buffer. A real-life buffer will exhibit a small output resistance Rn, as shown in Fig. P5.38. (a) Show that Eq. (5.68) still holds, provided the term 11 R2yReq is changed to 1 1 [R2 1 Rn(11 R2yR1)]yReq. (b) If a CFA with Req 5 750 kV and Rn 5 40 V is confi gured as a noninverting amplifi er with R2 5 9R1 5 1.2 kV, fi nd its gain A. What is its percentage deviation from the ideal? How does it compare with the case Rn 5 0?