We found this circuit in a 1967 Electronic design. However, it can be easily implemented even today as it uses only common diodes.
Epson SG 8018 Epson Crystal Programmable Oscillators Available from Mouser Electronics, these...
When the lights turns off this circuit will produce a sound like a cricket. When the lights are...
This circuit appears elsewhere on the site. The circuit shown is from an American 1980s...