This indicator with the integrated circuits CA3162E and 3161E was published in the July 1990 issue of Radio Electronics magazine. The circuit can be used as a basis for 3-digit projects.
We have dozens of similar projects in articles and circuits on this site. This is from Radio...
This circuit with an unusual configuration was found in the January 1974 issue of Radio...
This interesting circuit from 1967 documentation uses three series lamps to regulate the voltage...