This circuit was obtained in an Electronics World of 1968. The operational amplifiers ones are types of the time, no longer used today. The circuit responds from less than 20 Hz.
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....