Electronically Adjustable Capacitance Multiplier Circuit with a Single Voltage Differencing Gain Amplifier (VDGA)

In this work, we propose a resistorless realization of the simple capacitance multiplier circuit with electronically controllable using a single voltage differencing gain amplifier (VDGA) as an active building block.  The circuit utilizes one VDGA and only one capacitor in a simple circuit configuration. The proposed capacitance multiplier circuit can be tuned electronically with the adjustment of the transconductance gains of the VDGA.  To emphasis the workability of the proposed circuit, the second-order RC low-pass filter is constructed as an application example.  PSPICE simulations are performed to verify the theory.