Produced by Westinghouse during WWII, this film explains how electronic vacuum tubes work from the simple diode (single pole switch) to the complex Cathode Ray tube.  As the film shows, tubes with grids can be used as electronic amplifiers, rectifiers, electronically controlled switches, oscillators, and for other purposes. Some of the innovations shown in the film include tubes used as rectifiers (for AC/DC conversion and production of metal such as aluminum), an early kind of tube based electrostatic air purifier called a Precipitron, tubes used in radio transmitters and radio telephones (as seen around the 00:08:10:00 mark), for remote control, analysis and testing,  for television, X-rays and more.  Manufacture of tin plate (00:11:32:00) is also shown, with tubes generating high frequency current to make the process possible.  Dialetric heating is shown being used to laminate plywood and test plastic, and increasing the load carrying capacity of transmission lines.  

At 00:10:20:00, a recreation is shown of the first radio broadcast made at the Westinghouse Studios of the electon of Warren G. Harding.

Electronic control of various systems in manufacturing is detailed starting around the 13 minute mark.  These systems provided an enormous edge for American manufacturing during the war by increasing efficiency.  Photo cells and tubes -- "electronic eyes" -- are shown operating relays, transforming light into current and transforming current into light.  (An early TV tube appears at the 16 minute mark).  Fluorescent tubes are also shown, and a discussion of sterile lamp rays is shown at about 18 minutes.  And one of the great developments of the war -- radar -- is shown at the 18:30 mark.

In electronics, vacuum tube, electron tube (in North America), tube, or valve (in British English) is a device that controls electric current through a vacuum in a sealed container. Vacuum tubes mostly rely on thermionic emission of electrons from a hot filament or a cathode heated by the filament. This type is called a thermionic tube or thermionic valve. A phototube, however, achieves electron emission through the photoelectric effect. Not all electron tubes contain vacuum: gas-filled tubes are devices that rely on the properties of a discharge through an ionized gas.

The simplest vacuum tube, the diode, contains only an electron emitting cathode and an electron collecting plate. Current can only flow in one direction through the device between the two electrodes, as electrons emitted by the hot cathode travel through the tube and are collected by the anode. Adding control grids within the tube allows control of the current between the two electrodes. 

Invented in about 1910, vacuum tubes were a basic component for electronics throughout the first half of the twentieth century, which saw the diffusion of radio, television, radar, sound reinforcement, sound recording and reproduction, large telephone networks, analog and digital computers, and industrial process control. Although some applications had counterparts using earlier technologies such as the spark gap transmitter or mechanical computers, it was the invention of the vacuum tubes that made these technologies widespread and practical. In the forties the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, more efficient, more reliable, more durable, and cheaper than tubes. Hence, in the '50s and '60s, solid-state devices such as transistors gradually replaced tubes. The cathode-ray tube (CRT) remained the basis for televisions and video monitors until superseded in the 21st century. However there are still a few applications for which tubes are preferred to semiconductors; for example, the magnetron used in microwave ovens, and certain high frequency amplifiers.

This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD and 2K. For more information visit http://www.PeriscopeFilm.com