10 Band Graphic Equalizer Circuit | Homemade Circuit Projects Jun 17, 2019How the 10 band graphic equalizer circuit functions. Consider an AC voltage source Vi connected to the opamp stage. This pushes a current Ic via the capacitor (C1, C2, C3 etc), which constitutes a proportional voltage across the connected ground resistance (R11, R12, R13 etc). 20 Band Graphic Equalizer - Circuit Schematic Here the 20 band graphic equalizer schematic diagram. This is stereo graphic equalizer, it should be 2×10 channel equalizer. Graphic equalizers device are popular with both domestic users and professional users. This equalizer is has simple design and easy to construct. It has no coil.