Found in Popular Electronics from the 90s, this circuit turns off an appliance at the end of the programmed time. The 12 V relay must have contacts according to the controlled current.
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....