# Homework Help: Operational Amplifier Homework Question

1. Dec 8, 2016

### Ariastity

1. The problem statement, all variables and given/known data
What is the value of V2 in terms of Vos?

2. Relevant equations

3. The attempt at a solution
In the class, we were told that this is just a non-inverting amplifier, thus V2= Vos x (R2/R1+R2).
However, I want to work out the solution by applying nullator hypothesis (voltage difference between the two op amp inputs is 0) only, without realising that the top part is a potential divider.

Is it correct to assume that the voltage across R1 is Vos? That way, I can get the current i to solve for the voltage across R2.
http://[PLAIN]http://i64.tinypic.com/a0i5hs.jpg [Broken]
http://i64.tinypic.com/a0i5hs.jpg

Last edited by a moderator: May 8, 2017
2. Dec 8, 2016

### Staff: Mentor

Yes, that's a valid assumption here.

3. Dec 11, 2016

### rude man

A non-inverting op amp gain is always >=1 unless the feedback is active (another amplifier section). So I hope you were not told that ...
... and I assume you meant Vos x R2/(R1+R2) otherwise your equation is dimensionally wrong.

4. Dec 12, 2016

### LvW

Yes - with this assumption you get I=Vos/R1=(V2-Vos)/R2.
This equation can simply be solved for V2.

Last edited by a moderator: May 8, 2017