(a) Replace the BJT of with its smallsignal model, and use the test-signal method to prove that the resistance seen looking into the output port with the input port opencircuited, as shown, is (b)...

(a) Replace the BJT of with its smallsignal model, and use the test-signal method to prove that the resistance seen looking into the output port with the input port opencircuited, as shown, is

(b) Calculate Ro if RF 5 10 kV, RC 5 1 kV, and the BJT has F 5 100, VA 5 100 V, and is biased at IC 5 1 mA. (c) Discuss the limiting case RF → 0 and RC → `, and justify your result in terms of already familiar BJT behavior. (d) Repeat part (c), but with an ac short-circuit across the input port.