Hi;
We know in FET transistors gm is delta(Id) / delta(Vgs)| Vds=cte
and rds is  delta(Vds) / delta(Id)| Vgs=cte.

Do you know if there are any ways that we can plot the value of gm versus Id for Vds=cte and parametric change of Vgs and the value of rds versus Id for Vgs=cte and parametric change of Vds or any other way  in Affirma environment?

Ofcourse for gm we can plot Id-Vgs and the tangent value at each point gives gm at that point but I want to know if we can plot that tangent faunction and also it is right that we can calculate gm knowing Id, Kp and W/L and calculate rds knowing lambda and Id but even Kp and Lambda could depend on other parameters like u0 or L and  if we have a good model for the transistor, it should worth to draw gm and rds with no need to worry about nonideal effects or short channel effect in calculation.

Best
Babak

Thanks for your help Mighty Mouse
It actually worked and also I did parametric analysis on dc value of Vgs to change the baising point while running ac analysis to have gm plot for different biasing situation.

Thanks again
Babak