We found this configuration in documentation from the 1980s. It applies to almost any operational amplifier and in this version requires a symmetrical power supply.
In the figure we show a way to change the output voltage of a fixed regulator, such as 7805 or...
This circuit is from an old American publication, using transistors of the time and operating with a 48...
This control, which may appear in other versions on this site, was found in documentation from the...