Silent alarm (CB22471E)

This circuit is from a Popular Electronics from 1992. The circuit powers an LED when triggered.

Electronic Target Shooting (CB18173E)
This circuit is from a 1982 documentation. It can be modernized using LEDs in series with 470 ohms...
Multiple Alarm (CB20628E)
We found this circuit in a 1985 technical publication. The circuit uses PUTs to drive lamps....
741 Twin-T Oscillator (CB19351E)
This circuit appears with variations in other points of this section. This version is from...