CW tone generator (CB21673E)

This telegraphy circuit generates an audio tone from a pure RF carrier. We found it in a publication by Gernsback from 1960.

4040 Oscillator (CB14984E)
This traditional rectangular oscillator configuration generates signals up to a few megahertz...
Music Generator (CB9882E)
This circuit is just a curiosity found in a 1990 documentation, since the integrated circuit used...
Voltage Drop Alarm (CB1530E)
This circuit goes into operation producing a sound on a small speaker when the supply voltage...