a) For the CG amplifier in Fig. 8.18(a), show that thecurrent gain i,/i is given by \frac{i_{o}}{i_{\text {sig }}}=\frac{R_{\text {s }}}{R_{\text {s }}+R_{\text {in }}} O For the case g,

=2 mA/V, r, = 20 k2, and R, = 20 kN,find the current gain obtained with R,%3D20 kN.%3D (c) If R, is doubled (that is, increased by 100%), find the corresponding percentage change in current gain. If R, is increased from 20 kohms to 200 kohms (that is,increased by 900%), what is the corresponding change in current gain? e) Using the results of (c) and (d), comment on the performance of the CG circuit as a current buffer.