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.
This circuit is from a Popular Electronics of December 1993. In it we have the way to externally connect...
With this power supply it is possible to use automotive devices with currents up to about 8A on the...
This circuit was found in a 80’s American documentation. The adjustment trimpot is from 47k to...