This circuit was found in a 90s American publication. The same configuration appears in several places on this site, obtained from different sources. The lamps can be replaced by LEDs.
The output voltage of this unit is approximately 1.4 V less than that of the chosen zener. The...
Found in the April 1980 issue of Radio Electronics magazine, this stage uses transistors from the...
To control direct current loads, under voltages between 12 and 200 V, and currents up to 3 A, we...