This telegraphy circuit generates an audio tone from a pure RF carrier. We found it in a publication by Gernsback from 1960.
This circuit was taken from a Popular Electronics from the 1990s. The circuit triggers a relay that...
Found in a Popular Electronics from the 90s, this theremin is played by the position of the hand...
We found this circuit in a transistor manual from the 1960s. The transistor is the Germanium...