30 MHz Amplifier (CB5939E)

This low noise circuit was obtained from a 1980s US RF publication. Transistors used are uncommon today and the gain is 19 dB..

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Genera-Purpose Alarm (CB10326E)
This simple circuit was obtained from Popular Electronics in December 1990. The magazine no longer...
Sound receiver (CB8231E)
Indicated by a 90s Popular Electronics, this circuit amplifies acoustic signals for analysis on an...
Stable VFO (CB4050E
) This variable frequency oscillator was found in an old American documentation. Transistors allow more...