The cut-off frequency of the circuit shown in the figure is 750 Hz, with the components used. The circuit applies to almost any operational amplifier and the power supply must be symmetrical.
This circuit was published in a 1977 English magazine, but remains current, since we can assemble it...
Circuits like this one, using the LM386 audio amplifier, are available from other sources in this...
This configuration from the 1970s can be applied to modern equivalent operational amplifiers. The...