I must have spent 20 hours on this question and still i have not prevailed with an answer.
Every time i end up stuck with to many unknowns. So circuit 1 is the general circuit, circuit 2 is DC model, Circuit 3 is small signal model
So from the beginning.
- Assume saturation mode.
- Because drain current is given and gm, VGS(DC) can be accordingly be solved. Gm=1mS VGS(DC)=1.5 V
- Issue in DC analysis. when drawing DC model you short all small signal voltage sources. Now at Vin in the second schematic. does that get short circuited because somewhere behind that point there must most definitely be an small signal source. If it it short circuited the VGS DC value of 1.5 V is not possible.therefor presumably it must be left as an open circuit? to have a 1.5 VGS value? This delema would not be an issue if there was a cap in the diagram and then the Vin source. unfortunately not the case.
- Vout in dc analysis left as an open circuit
- Move to small signal analysis
- See working out in attatched image. KVL from Vin->R1-> Ground and KVL vin->R2->R3->ground applied. Not that Rin = Vin/Iin. Apply 1 V test voltage to Vin. coresponding I Test= 2x10^-6 A.
- Results in expression for R2 in terms of a constant and I2 and an expression for R1 in terms of I1
- From here? I'm not sure