This charger was found in an 80's Electronic Design. The circuit uses components from that time. Equivalents can be tested.
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...