This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is not an easy component to obtain and the power can be supplied with a single button cell.
This National Semiconductor circuit appears elsewhere on this site. The circuit must be powered by...
Found in the May 1997 issue of Electronics Now, this circuit produces a variety of sound effects for...
We find this vibrato configuration with transistors in a 1987 documentation. The components are still...