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.
Found in American documentation from 1968, this circuit has an acute cut-off of the frequency to...
This simple circuit was found in the Spanish magazine “Todo Electronica”, in an edition of 1996....
This circuit of an old medical publication makes use of an integrated circuit of the time,...