This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
This configuration appears elsewhere on this site. We obtained it from a 90s Radio Electronics, based...
This circuit is from a Fairchild digital clock module shown in the March 1977 issue of Radio...
This good power amplifier, a few tens of watts, is part of an article in the December 1972 Radio...