(a) Assuming the FET of Fig. P4.16 is operating in the active mode, derive an expression for the small-signal resistance R. (b) Discuss the limiting cases RS → 0 and ro → `, and justify them in terms...

(a) Assuming the FET of Fig. P4.16 is operating in the active mode, derive an expression for the small-signal resistance R. (b) Discuss the limiting cases RS → 0 and ro → `, and justify them in terms of known MOSFET properties. Hint: replace the FET with its small-signal model, and use the test method.