We found this simple circuit in December 1975 Radio Electronics magazine. The integrated circuit is the 4009 CMOS, and the circuit works in both TTL and CMOS depending on the power supply.
The CK722 transistor used in this circuit is one of the first commercial types in the world. The...
This automatic dimmer for incandescent lamps was found in a European publication from the 1980s. The...
This traditional doubler configuration with the 555 can be found in other articles on the author’s site....