We found this time base of 0.1 to 90 seconds in a circuit manual from the 90s. The single-use transistors used are common and the frequencies given by the adjustment by the potentiometer.
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....