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 oscillator with the 4049 can generate signals up to about 14 MHz according to the article in the...
This simple receiver, which requires a good antenna and grounding, was found in an Argentine...
This setting is valid for other transconductance operational amplifiers. The circuit is from...