Using 4 tubes, this 1924 receiver combines new technologies as an intermediate frequency stage that was already beginning to appear. Listening is via phone and battery power.
One of the problems with common 3-terminal regulators is that the internal reference, normally 1.25 V,...
This windshield wiper interval was found in old documentation. The NPN transistor is general...
This circuit was found in a Radio Escuela Gráfica magazine from Argentina published in the 70's....