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Could anyone explain the role of resistor R1 in the circuit below?

Thank you.

enter image description here

emnha
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    Try read this http://e2e.ti.com/blogs_/archives/b/thesignal/archive/2012/04/11/input-bias-current-cancelation-resistors-do-you-really-need-them – G36 Jun 16 '16 at 14:22
  • I'll put a resistor there if it is the input to the circuit from the outside world. sorta cheap over voltage protection.. maybe 1 k ohm or so. – George Herold Jun 16 '16 at 14:26

1 Answers1

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The input signal to the op amp might "see" frequency dependent impedance behavior... This can be caused by circuit parasitics or other known elements such as long feeding leads.

Thus in order to establish more predictable response this resistance will be needed.

soosai steven
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