This circuit was found in a 1980s documentation for amateur radio. The circuit is for 9 MHz signals and values in parentheses for FI of 455 kHz. The circuit can be adapted to other frequencies.
This circuit was found in a 1982 Maplin publication. The circuit is tuned to recognize a 400 Hz...
The sensor component used in this project is not common today as it is an 80's design. The circuit...
This LED light effects circuit is from 1988, but uses common components nowadays. The LEDs are...