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Difference amplifier

  1. Feb 13, 2007 #1
    I know the output voltage for a difference amp is (R2/R1)(V2-V1) but how do you find the output voltage when you connect the circuit attached to the difference amp where V1 and V2 are the input voltages to the difference amp?

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  2. jcsd
  3. Feb 14, 2007 #2
    Apply the usual rules for ideal op amps. That is, the voltage between the inverting and noninverting terminals is zero and the current flowing into these terminals is zero.

    It may then be helpful to write the output voltage as a function of the source current. A loop equation will relate the source current to the source voltage.
  4. Feb 28, 2007 #3


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    Staff: Mentor

    mdelisio did help. Show us your work so far, and we can help if you're stuck on something or making some math errors.

    Welcome to the PF, BTW. Note though that homework and coursework will generally need to get posted in the Homework Help forums, and you need to show your work so far in order for us to help you (PF rules). I let this thread stay here in the general EE forum up to now, but if it turns into a homework thread I'll go ahead and move it over to the Engineering Homework Help forum.
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