This circuit was found in February 1976, Radio Electronics magazine. The components are from the time and are based on the 555. The power supply must be provided with the indicated voltages.
Using components from the era, this 90's EDN circuit is used in analog to digital conversion...
Found in an American publication from the 90s, this circuit allows the supply of 3, 6 and 9 V...
We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED...