How can i know Vds in advance before simulation?

[Tesla Gwon]

i think this question is very important.
We must know Vds to make MOSFETs in saturation region.
if not, there would always be possibilities that a transistor falls in a linear region as Vds is lower than Vdsat.

Of course, i can calculate Vds in a CS AMP with a drain resistor.
I mean, in the other configurations, we should also know Vds.

How can i calculate it?

 

[Jony130]

Well you need to use your circuit theory knowledge and solve for Vds.
Also you can show as a circuit that you have a problem with.

 

[meBigGuy]

Your question is confusing me.

I really don't understand what you are asking.

Read the following and try asking your question again:
http://electronics.stackexchange.com/questions/18885/mosfet-as-a-switch-when-is-it-in-saturation