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 high quality circuit with complementary symmetry was found in an Electronics World of 1966....
Found in an Electronic Design this circuit controls a headlamp by triggering a time determined by the...
This small switched regulator was found in an 60’s Optical Electronics. The circuit uses an...