In use telephone indicator (CB8665E)

This circuit was found in a 90s Electronics Now. The circuit can use a TIC106 for the SCR.

Simple 555 Timer (CB12816E)
With a touch of the sensor wire X1, which can also be a pressure switch, the LED lights for a time...
Precision Optical Level Detector (CB4955E)
This circuit is from the 80's and can be implemented with modern equivalent components. R1 is 2M5,...
Triac On-Off Power Control (CB24045E)
This conventional bistable power control circuit using triac was found in the June 1970 Radio...