This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics magazine. The source must be symmetrical. The capacitors can be changed for other frequencies.
We found this receiver circuit for modulated light in a 90s Popular Electronics. Equivalent audio...
What differentiates this circuit from the many versions with the 4017, presented in our...
This circuit was found in a 90s Popular Electronics. The integrated circuit used is similar to the 741....