Relative impedance meter (CB7487E)

Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent transistor like the BC558.

Radio Spica ST-800 (CB11571E)
This circuit is for collectors. It is the circuit of one of the most popular transistor radios of the...
Electronic Fuse (CB25411E)
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...
1 W CW transmitter (CB7432E)
Found in a QST magazine from the 90s, this circuit broadcasts on different amateur radio bands...