Geiger counter with high voltage source (CB22333E)

This circuit includes a high voltage inverter to power a Geiger tube. We found it in an American documentation from the 60s.

Stereo preamplifier (CB8510E)
Found in a 90s Popular Electronics, this circuit is based on a uA739, an unusual component today....
Accelerated Sequential with the 4017 (CB12138E)
This circuit is from a 1982 publication. It is a sequential effect of accelerated LEDs. The...
Transistor Infrared Sensor (CB4581E)
In the figure we have more circuit that makes use of transistors and that has excellent...