what is the feedback type of the inverting amp?

[llbaobao]

Though I have read the feedback chapter in books, still I can not analysis it.

The simplest inverting amp use what kinds of feedback?
volt-volt feedback? current-volt feedback? or others?

Please help me.

 

[LvW]

The inverting opamp applies voltage controlled current feedback.
Explanation: The input parameter of the inverting opamp must be regarded as a current (because the voltage is not applied directly at the input pin but via R1) - and this current is superimposed with another current driven by the output voltage via R2.
As a result - two currents are added at the inverting input node and create a voltage which is very small (mikrovolts) and which is amplified by the open loop gain.
Thereby, the input resistance of the whole circuit goes down to a value which is app. identical to r1.

 

[llbaobao]

thank you very much!

Though I have studied many theories, I can not use them freely.

Thank you.