Figure 9.42 (a) Equivalent circuit for the amplifier in Fig. 9.41(a). (b) Simplified equivalent circuit. Note
that the equivalent circuits in (a) and (b) also apply to the circuit shown in Fig. 9.41(b). In addition, they can
be easily adapted for the MOSFET circuit in Fig. 9.41(c), with 2rπ eliminated, Cπ replaced with Cgs, Cμ
replaced with Cgd , and Vπ replaced with Vgs.