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.
We find this circuit in an American publication of 1978. The integrated circuit is the CMOS 4013...
This circuit is a modification of the previous one, also found in the July 1995 Electronics Now...
This circuit was found in a 1968 EEE and can be implemented with any current general-purpose transistor....