Small signal model for MOSFET...unsure as to whether it is common drain, gate, or source

Question

I am looking to solve for the input/output resistance in the small signal model for the below circuit. But, I am unsure as to how to set up the model as I can't tell if it is common gate/source/or drain. I know in small signal the capacitors will act as shorts.. but from there I am pretty lost in the schematic. I've solved for Vgs, Idrain and Vds already in the DC bias model.

Will Vin be 0 since its shorted to ground?

Answer 1

It is a common gate amplifier. The input ( small signal) is being applied at the source and is measured at the drain.

I know in small signal the capacitors will act as shorts.. but from there I am pretty lost in the schematic

-- This is not correct. The capacitors will act as shorts at high frequency and is not dependent on the small signal model usage.

Hope that helps.