Hi! In a theoretical sense, they can be whatever you want. So if V1=10V and V2=20V, then, as an unscaled summer, V0=-30V. And as an average circuit, V0=-15V. However, in a physical circuit, the limits of the inputs and the resultant output would depend on what physical OpAmp you end up using. For example, a typical 741 OpAmp can only output up to around +/-20V (see LM741A datasheets). Hope that helps! 😁

I guess some things don't change. 😊

Hi Salman. Apologies for getting back so late. If you use Miller's Theorem, you have to understand that the assumption is that no current flows into the input of the amplifier. Obviously that's not the case here as I_B (for biasing) and i_B (from the signal), are not zero amps. So the derived expression via Miller's Theorem will not be the same as per my derivation, as I do not assume zero amp input current. Hope that helps. 😊

Hi David. I've just uploaded one version of it here: kzbin.info/www/bejne/baOmZHqNqqyonbMsi=jTGA-JlxrPck_PNr

Instead of using Miller's Theorem, the analysis here is based off Ohm's law, KVL, KCL, etc. Any specific part of the derivation that you're not clear about?

Hi David. Thx! Can you be specific which -ve sign you're referring to?

THE CURRENT GAIN - ALPHA.

@@davidluther3955 Alpha is not negative. The negative comes from the fact that the current (alpha x I_e) is equal in magnitude to I_o, but in the opposite direction.

THANK YOU FOR TIME!

Yup. A necessary skill in the age of the pandemic when my handwriting work isn't much to look at. 😁

Salam Sulaiman. Glad that you liked my approach! Nothing fancy about the diagrams though; they are what's available on the Net and I just use Paint to add or remove things. All the best in your learning journey! 😊