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  1. #1
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    Isolate R37 from Equation

    Hi,

    I need to Isolate R37 from the attached Equation.

    The Resistors and Vo, Vf,VCC need to be in the equation.

    Any Solution?

    Thanks,

    Doron

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  2. #2
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    Re: Isolate R37 from Equation

    R37 is a very important part of the circuit since it and R42 set the input voltage of the opamp, then since the opamp has a gain of 1 the output voltage of the opamp is also set to be the same as the input voltage.



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  3. #3
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    Re: Isolate R37 from Equation

    try this:
    apply voltage divider at the + input of the op amp V+ = ...

    assuming a perfect op amp, V- and output = V+

    combine R25 and R28 to one equivalent resistor

    assuming Vo is open, apply voltage divider (Vf, R21, V+ and equivalent R25-R28)

    when you have Vo = ..., replace V+ with what you got above

    follow the rules of algebra
    expand everything so there are no parenthesis and no fractions
    put all terms with R37 on one side of =, everything else on the other side
    factor out R37 and divide



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