(a) Replace the FET of with its smallsignal model, and use the test-signal method to obtain an expression for Rds. What is the function of RF in this circuit? (b) Calculate Rds if RF 5 1.0 MV and RD 5...

(a) Replace the FET of with its smallsignal model, and use the test-signal method to obtain an expression for Rds. What is the function of RF in this circuit? (b) Calculate Rds if RF 5 1.0 MV and RD 5 10 kV, and the FET has gm 5 1.0 mA/V and ro 5 100 kV. (c) What happens if the gate and source terminals are ac shorted together?