Relative impedance meter (CB7487E)

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

Digital Clock Generator (CB24246E)
This TTL circuit is from a Radio Electronics magazine from February 1973. The circuit must be...
Operational RIAA Preamplifier (CB14846E)
Common operational amplifiers like the TL series, CA3140 and others can be used in this circuit...
Telegraphy Practice Oscillator (CB16348E)
This circuit uses only two common transistors and provides good audio power in a speaker. Readers who...