The inductor coil is one of the fundamental electronic components however it is very less used in the electronic circuits as compared to the other components. The reasons are mainly due to its physical size, sensitivity to the presence of electromagnetic field, unavailability of wide range of inductance values etc. The inductors cannot be included in the Integrated Circuit Chips due to its three dimensional geometry and size. Hence most of the circuit designers try to avoid inductor coils from their circuits and prefer ‘Synthetic Inductor Circuits’ which simulates an inductor using other electronic components.
This article discusses on the design of a Synthetic Inductor circuit and demonstrates its working on a sample application circuit. The Synthetic Inductor can be easily made using a capacitor, Op-amp, a resistor and a variable resistor using which the inductance value can be varied by a large range. When using SMD components the entire circuit will take less space than the actual inductor.
Here the Synthetic Inductor is used to realize a simple high pass filter which can remove the low frequency sounds from a normal audio input. The high frequencies are separated from the low frequency bass-treble before it is fed to normal loudspeakers since they cannot effectively reproduce bass-treble like the woofers does.
Synthetic Inductor Based High Pass Audio Filter