This circuit that uses potentiometer tuning, was found in a documentation from the 80's. The integrated circuit used is from that time and is a not common today.
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....