AC voltage control (CB8904E)

This circuit was found in a 90s Hands On Electronics. The semiconductor component is a Triac of the time.

Blown Fuse Alarm (CB4875E)
This 3V-only circuit was found in old American documentation, but can be implemented with...
Variable Regulator 0 to 1 A (CB1195E)
The output voltage of this circuit, which can regulate the current in a load between 0 and 1 A,...
Temperature compensator for VFO (CB8096E)
This circuit was found in a Popular Electronics from the 90s. The circuit has temperature...