Indicated for the protection of three-phase systems, this circuit was found in an American documentation of the 70's. The circuit can be implemented with modern components.
This transmitter for the 40 meter or 7 MHz band was found in a magazine 73 for radio amateurs of...
This shortwave preselector was found in the July 1994 issue of Radio Electronics magazine. The...
This circuit was found in a 1967 RCA documentation. The components are of the time. The circuit...