Figure 3.

Schematic diagram of the self-balanced bridge. The current $i_x$ flowing through the admittance to be measured, $Y_x=G_x+\mathbf{j}{C}_{x}2\pi f$, under bridge oscillator voltage $v_{osc}$ at frequency f, is balanced by the current $i_{eq}$. It is generated by the bridge owing to a feed back loop, multipliers and fixed components, conductance $G_{eq}$ and capacitance $C_{eq}$. The feed back loop provides the direct voltages $V_G$ and $V_C$.