This interesting circuit of an Electronic Design stores the highest voltage of two applied to its inputs. The circuit is from 1964 and can be adapted to use modern components.
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
This adjustable source from 2 to 15 V uses transistors from the 60's, as indicated in the...
Found in a 90s Popular Electronics, this circuit is intended for amplifying analog video signals....