Circuit for measuring small alterations of electric variables, especially capacitances

摘要

The feedback of the output signal is fed to the input of the first operation amplifier (OPV1), across a nonlinear network, with which a nonlinear function is realized using a cubic current-voltage performance curve. The nonlinear network consists of two parallel diodes (D1,D2) connected opposed and resistances and an auxiliary resistance connected in parallel to the diodes with a further resistance in series.