This circuit was found in the February 1983 issue of Radio Electronics magazine. It is a 4-digit circuit with dedicated integrated circuits, with no power supply indicated.
Any general purpose PNP transistor such as the BC558 can be used on this circuit from an old...
This circuit is from a 1965 General Electric hobby manual. The circuit can be assembled with...
This circuit was found in a Maxim documentation from the 90s. It is valid for the lower income types...