This circuit is from a 1924 book by Gernsback. The receiver uses two tubes and listens to headphones. Power is supplied by battery with the indicated voltages.
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
This circuit was obtained in a 1967 Raytheon manual. The company's component is an optical coupler with...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...