Op-Amp vs Precision Resistor: Which is Better for I-to-V Conversion?

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riie
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Hi all,

What is the difference of using an op-amp(transimpedance) vs a precision resistor to convert I-to-V?

I am trying to linearly amplify a 1nA-10nA AC current with frequency of 10khz and below to a AC voltage and be passed to other circuitry for further processing.

Thank you for the help, in advance.
 
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If you use a precision resistor, the voltage across it may affect the current that you are trying to measure. A transimpedance amplifier will, effectively, be present a low impedance load to your current source and not affect the current. Of course, using a low enough resistor and then measuring a very small voltage would be an alternative. . . . .