Battery Monitor (CB6067E)

This simple circuit has its trigger point set in the trimpot. The transistor can be any general purpose and the LED of any color.

Epson SG 8018 Crystal Programmable Oscillators
Epson SG 8018 Epson Crystal Programmable Oscillators Available from Mouser Electronics, these...
Electronic Cricket (CB795E)
When the lights turns off this circuit will produce a sound like a cricket. When the lights are...
Limit Comparator (CB5086E)
This circuit appears elsewhere on the site. The circuit shown is from an American 1980s...