Found in na 1970 EDN this circuit has a parallel regulation providing a symmetrical output of 15 V. The transistors are from that time.
This amplifier was found in a Japanese publication in 1972. Transistors are uncommon today, and...
The current of this source is 200 mA at the most, and the output depends on the zener that may...
Found in Mallory documentation from 1968 this circuit uses an integrated circuit from that time. The...