Found in a publication for radio amateurs from the 1980s, this circuit amplifies signals in the 60 kHz band (VLF), Winding data from the ferrite antenna are provided along with the diagram.
This circuit can work with almost any JFET. The circuit is from an Electronics Now from April...
This physical line servo control uses components that are not currently common. The circuit is from...
This circuit was found in a British documentation from 1969. It can be implemented with modern...