Found in American documentation from the 1980s, this circuit has a diode feedback. At the exit we have an indicator LED. The LM3900 is a transconductance operational amplifier.
The author of this project found in a 1980 documentation gives the radio in two versions: the...
Found in the August 1982 issue of Radio Electronics magazine, this circuit lights LEDs in sequence...
CTS IoT Quartz Crystals Available through Mouser Electronics, CTS quartz crystals are especially suited...