Hello guys i facing a problem of inverting configuaration of opamp



in this configuration,the current start flowing through Ri, Rf to Vout, due to high input impedance no current flows to the input terminal of op-amp,
so my question was if there is no current flowing in the inverting terminal of the op-amp then how the output waveform is shifted 180 degree out of phase
by mathematical calculation im able to find the inverted output signal, at the output pin of op-amp,
but by practically im getting bit difficult to analyse how the signal is getting shifted 180 degree

please suggest how i can analyse the circuit properly

 

in this configuration,the current start flowing through Ri, Rf to Vout,

That is the mistake. The input current is nulled at the inverting input by a contrary current sent from the op-amp through the feedback resistor. The input current does not flow through to the output.

 

Add to that the fact that there is current going into the inputs, just not very much in the case of bipolar inputs and in the case of FET inputs even less current. There is also a very tiny signal voltage across the + and - inputs. The higher the loop gain the smaller this signal.