This commercial 6-digit clock circuit was found in August 1976 Radio Electronics magazine. Note the supply voltages and the use of a period module.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...