1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Operational Amplifier Homework Question

  1. Dec 8, 2016 #1
    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]

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


    User Avatar

    Staff: Mentor

    Yes, that's a valid assumption here.
  4. Dec 11, 2016 #3

    rude man

    User Avatar
    Homework Helper
    Gold Member

    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.
  5. Dec 12, 2016 #4


    User Avatar

    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
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted