Found in RCA documentation from the 1960s, this 60 V regulator has a 100 V input and a current of 1 A. The transistors are from that time. One can try to use modern equivalents.
This circuit was found in the March 1997 Electronics Now magazine. It uses a common analog...
This tunnel diode circuit was found in American documentation from 1966. The tunnel diode is the...
This circuit was found in the comparator's own documentation, serving others in the same series. The...