This circuit was found in a 1980s documentation for amateur radio. The circuit makes use of components of the era, but modern equivalents can be used.
Found in a 90’s Radio Electronics, this circuit uses a component from the time, difficult to find today....
We found this circuit in a 1996 publication. The circuit uses components that are still common. The...
This 1 kHz filter was found in the March 1997 issue of Electronics Now magazine. The circuit is...