Guarda su StreamingCommunity. With Western Electric Vacuum Tubes in the starring roles, this film tells the fascinating story of tube development from the first crude bulbs of Edison and De Forest to the powerful and efficient tubes in use today, and shows the prominent part they play in radio, long-distance telephony, public address systems, sound motion pictures and the phonograph.
- Genere:
- Nazione:
- Direttore:
- Cast: