NMOS Common source DC-bias and gain

[Waxterzz]

Homework Statement

V_OUT, they mean DC

Homework Equations

See picture, r0 is neglected also lambda (channel modulation)

The Attempt at a Solution

I calculate I _DS with the formule given: 0.400*(0.5)²=0.1 mA

I_OUT = 5/25000 = 0.2 mA

So the current source has got to be 0.1 + 0.2 = 0.3mA. Thats the DC current it has to be delivered right?

I also had to calculate the AC gain:

g_m = K (V_GS - V_T) = 0.4mA/V

v_in = v_gs

v_out / v_gs = -g_m * v_gs * R_D = -10This correct?

 

[rude man]

If the thing in series with the +10V supply is indeed a current source labeled I_D then you computed I_D correctly.

A good first step is always to define the problem accurately.

You also have computed the ac gain correctly.

 

[Waxterzz]

If the thing in series with the +10V supply is indeed a current source labeled I_D then you computed I_D correctly.

A good first step is always to define the problem accurately.

You also have computed the ac gain correctly.

Yes, I was also confused about the current source symbol. :) But it is one indeed.

Thanks for the confirmation that my calculations are correct.