Response to the following :
Consider an NMOS transistor having kn = 10 mA/V2. Let the transistor be biased at VOV = 0.2 V. For operation in saturation, what dc bias current ID results? If a 0.02-V signal is superimposed on VGS, find the corresponding increment in collector current by evaluating the total collector current iD and subtracting the dc bias current ID. Repeat for a -0.02-V signal. Use these results to estimate gm of the FET at this bias point. Compare with the value of gm.