Silent alarm (CB22471E)

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

Resistive Sensor LED Control II (CB1299E)
This simple circuit controls the brightness of an LED from LDRs, NTCs, PTCs or other resistive sensors....
Sound Roulette (CB16966E)
We found this circuit in a 1990 documentation. It draws one out of 10 numbers and during the draw...
Sawtooth generator (CB23731E)
The circuit shown in figure 3 uses a programmable unijunction transistor (PUT) of the BRY39 type...