This circuit is from a 60's documentation. The circuit uses components from the era and serves to monitor a 150V continuous power line.
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...