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Homework Help: Non inverting op-amp

  1. Dec 1, 2009 #1
    1. The problem statement, all variables and given/known data
    Calculate the out put voltsge on the amplifier with a voltage supply of Vs 100 mV and Rs = 1k , R1=1k R2=10k. power comes from a +-15 v supply


    2. Relevant equations
    V1-V2/r1+V1-V2/R2=0

    V+=V-


    3. The attempt at a solution

    it is the Risistor Rs that i am have trouble with since V+=V- on an op amp if i can find V+ then i think it can be done.
     

    Attached Files:

  2. jcsd
  3. Dec 1, 2009 #2

    berkeman

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    Staff: Mentor

    You correctly list V+ = V- which is true because of the high open loop gain of the opamp. The resistor Rs doesn't really do much in this circuit, since the input current of the opamp can be assumed to be negligible in a problem like this.

    So you are given Vs, which goes right into the V+ input. What voltage will you therefore have at the V- terminal? From there, it's just a voltage divider problem, right?
     
  4. Dec 1, 2009 #3
    thanks very much.
    did u like my diagram?. definatly not going to be an artist. haha
     
  5. Dec 1, 2009 #4

    berkeman

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    Staff: Mentor

    Hey, it worked for me. And thanks for posting with the HH Template and showing your work. Made it much easier to help you out. Welcome to the PF!
     
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