- #1

Martel

- 3

- 1

- Homework Statement
- Provided as pictures

- Relevant Equations
- Provided as pictures

I have to solve a problem related with an 'invented' (non-real) MOSFET working in its saturation region (amplifier). I have solved all the questions, but I'm unable to get the last one. Basically, I need to determine the output resistance of the amplifier as a function of other given 4 variables. I have read the book and I know that I'm supposed to apply a voltage test to the the amplifier's output, measure the obtained current and divide them to get the output resistance, which in the typical amplifier schema with a load resistor is exactly that load resistor (this is actually the situation in my problem).

The problem is that I need to express this answer as a function of other given 4 variables, and I have tried to do it like 1000 times and there is no way for getting what I need to do. The problem and the question is below:

The main problem's description:

The provided small signal model:

The question:

I have been able to obtain gm, which is K*VDS^2

Still, I just can't get the right result for the output resistance (ro). It should be R, but how can I express it as a function of the mentioned variables (notice I can't use VS).

The problem is that I need to express this answer as a function of other given 4 variables, and I have tried to do it like 1000 times and there is no way for getting what I need to do. The problem and the question is below:

The main problem's description:

The provided small signal model:

The question:

I have been able to obtain gm, which is K*VDS^2

Still, I just can't get the right result for the output resistance (ro). It should be R, but how can I express it as a function of the mentioned variables (notice I can't use VS).