Voice activated intercom (CB7828E)

This one-channel circuit was found in a 90s Popular Electronics, functioning as a vox. Components are common today.

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Symmetrical 2.5 A Power Source (CB17020E)
We found this circuit in a 1997 documentation. Power transistors must have good heat sinks. The...
Color Bar Generator (CB4649E)
This old circuit is from the era of analog televisions, serving for technicians to make...
Code Practice Unijunction Oscillator (CB1430E )
e find this circuit in documentation for radio amateurs of 1974. The unijunction transistor can be...