(Solved): [20\%] The n-channel MOSFET in the circuit below is at the DC operating point of ID=1mA,VDS ...

[20\%] The n-channel MOSFET in the circuit below is at the DC operating point of $$I_D=1\mathrm{mA},V_{DS}=1\mathrm{V}$$ and $$V_{GS}?V_{TN}=0.2\mathrm{V}$$. The transistor has negligible channel length modulation effect and body effect, i.e., $$?=0$$ and $$?=0$$. The two coupling capacitors have infinite capacitance. $$R_x=10\mathrm{k}?,R_S=10\mathrm{k}?$$, $$R_D=20\mathrm{k}?$$ and $$R_L=20\mathrm{k}?$$. a) Identify the circuit as a common-source, common-drain or common-gate amplifier. ( $$2\%)$$ b) Calculate the small-signal parameter $$g_m$$ and the current efficiency $$g_m/I_D$$ of the transistor. (3\%) c) The gate of the transistor in this circuit is an AC ground although no capacitor is used. Why? (2\%) d) Draw a small-signal AC equivalent of the circuit. The transistor must be represented by its smallsignal equivalent circuit. $$(6\%)$$ e) Find the overall small-signal AC current gain $$i_L/i_x?(7\%)$$