Chapter 7, Problem 7.62P

Figure P7.62 shows the high−frequency equivalent circuit of an FET, including a source resistance $r_s$ . (a) Derive an expression for the low− frequency current gain $A_i=I_o/I_i$ . (b) Assuming $R_i$ is very large, derive an expression for the current gain transfer function $A_i=I_o(s)/I_i(s)$ . (c) How does the magnitude of the current gain behave as $r_s$ increases?

Figure P7.62