For sensing capacitance value of sensors below circuit has common usage in literature.
I want to continue talking about simulated circuit in bottom.
Could be possible writing an equation similar to Vout/Vin=XC2/XC1 using virtual ground?(2nd pin of OPAMP)
XC1= 723ohm, XC2=723 ohm
Without R1 in the feedback path, output voltage negative rail saturated With R1, gain is -1 and output What is the role R1? What is the transfer function of this circuit?