This adjustable circuit from 0 to 200 nA was found in a 90's EDN. The components can still be found relatively easily, as they are CMOS.
This static switch circuit or solid-state contactor was found in a Motorola documentation from...
of the National Semiconductor of 1994. The same technique can be used with other operators and the...
Have you not yet memorized the color code used to identify resistors and capacitors? Do you have...