sheldon wrote on Aug 25th, 2006, 2:21am:bharat,
It is a little hard to understand what is happening from your description,
could you post a copy of your testbench.
Aaron,
In general it is better to work with the loop gain whentrying to understand
stability. Putting an amplifier inside of a loop can change its characteristics as
illustrated in Ken's book.
Best Regards,
Sheldon
I am partially answering the question what I have asked. It may help, to make my question more clear. Though there is no physical connection from output to input OR output to input is not shorted, but at higher frequencies the parasitic capacitances make virtual connection from output to input. For the analysis purpose, we take the worst case feedback factor, which is UNITY. So the loop gain A(s)f(s) turns out to be A(s) only
[f(s) = 1] and which is nothing but open loop gain.
Sheldon,
Does this explaination make sense? Therefore in text book analysis though we see openloop gain but due to specific value of f(s) it is equal to closed loop gain. I am not able to insert my testbench as image.
![Cry Cry](https://designers-guide.org/forum/Templates/Forum/default/cry.gif)
thanks
-Bharat