Phase and amplitude can be controlled in this circuit found in the May 1988 Radio Electronics magazine. The circuit requires a symmetrical power supply.
This configuration was obtained in a 1977 FET Databook. The circuit can be practically any JFET...
The integrated circuit used in this regulator is not very common today. The circuit is from old...
The operational used is uncommon today, but equivalents can be used. Unlike the previous one, this...