This circuit with the ULN3784B appeared in the October 1984 issue of Radio Electronics magazine. It can typically be powered from 9 to 24 V.
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....