At the height of the 1920s radio craze, a Western Electric engineer writes to his son to explain what really goes on inside his set. Letter by letter he builds up from electricity and matter, batteries and heated filaments to the audion tube, condensers and coils, transmitters, tuning, detectors and radio-telephony.
A friendly, clear introduction to early electronics, as rewarding now for curious minds as for vintage-radio fans. Download the free EPUB.