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Inverting Non-inverting Op-Amp Impedance

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satheeshvelu

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Inverting Op-Amp 1 with Rf=1kOhm, Ri=1kOhm. Gain = 0dB
Inverting Op-Amp 2 with Rf=0.1kOhm, Ri=0.1kOhm. Gain = 0dB

How much is the output impedance of Op-Amp 1 and Op-Amp 2?

Non-inverting Op-Amp 1 with Rf=1kOhm, Ri=1kOhm. Gain = 6dB
Non-inverting Op-Amp 2 with Rf=0.1kOhm, Ri=0.1kOhm. Gain = 6dB

How much is the output impedance of Op-Amp 1 and Op-Amp 2?

Someone please expand with the disadvantages in Op-Amp 2.
 

I don't know the accuracy you need for the answer to your question, however, the classical approach is as follows:
The output impedance of an opamp with feedback is
Rout=Ro/(1+LG) with Ro=opamp open-loop output resistance and LG=Loop gain.
In you case, LG is very large (half of the open-loop gain) with the consequence that the feedback resistor values can be neglected.
Thus, the same Rout in all cases.
But you must know that due to the LG function the output impedance is frequency dependent (and rising with frequency).
 
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