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Selective filter with a gyrator resonant circuit

This is a selective amplifier that manages by using the gyrator principle and therefor not needs a coil. In the specified dimensions, the center frequency is approximately 730 Hz (16000 / C in nF). The Q-factor is about 300 to 500, the voltage gain is abt. 300.

By parallel connection of a RC series combination of a 10 kOhm potentiometer and a 10μF capacitor (as little loss as possible) to the designated 10 kOhm resistor (*), the center frequency can be set approximately in the ratio 1: 5. In this way, the circuit can be used, for example, for so-called wah-wah effects in music electronics.

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