This circuit covers the bands from 1.8 to 150 MHz, with plug-in coils whose characteristics are given next to the diagram. The FET can be a BF245. We found it in old documentation.
This circuit provides a symmetrical voltage of 15 V output from the 6.3 V secondary of a small...
We found this circuit in an American 1980s documentation. The operational ones used are not common...
This transistor source can supply currents up to 2 A and the voltage determined by the zener...