This silent film made by Western Electric Co. details the manufacture of vacuum tubes for electronics. It likely dates to the early 1930s. The film starts with images of stems being made (1:00) with women feeding leads into die block at (2:00). At 2:20 finished stems are placed in an annealer from the die block. At 2:57 the Assembly Department is shown with staff, most of them women, working on the tubes by hand. At 3:58 spot welding of tubes is shown, with a woman dexterously moving a stem into the welding gun. At 5:18 the assembly is sealed in a bulb. At 7:31 vacuum tube exhaust stations are shown. At 7:55 a tube is sealed on an exhaust header. At 9:25 magnesium getter is flashed using high frequency electric current. At 9:50 filament, grid and plate leads are disassembled. At 11:30 the fire setting without measured pressure is shown.
Western Electric Company (WE, WECo) was an American electrical engineering and manufacturing company that served as the primary supplier to AT&T from 1881 to 1996, and to the local Bell Operating Companies until 1984. The company was responsible for many technological innovations and seminal developments in industrial management. It also served as the purchasing agent for the member companies of the Bell System.
In electronics, a vacuum tube, an electron tube or valve (British usage) or, colloquially, a tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.
The type known as a thermionic tube or thermionic valve uses the phenomenon of thermionic emission of electrons from a heated cathode and is used for a number of fundamental electronic functions such as signal amplification and current rectification.
Non-thermionic types, such as a vacuum phototube however, achieve electron emission through the photoelectric effect, and are used for such as the detection of light levels. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube.
The simplest vacuum tube, the diode invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode. Current can only flow in one direction through the device—from the cathode to the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grid or grids.[5] These devices became a key component of electronic circuits for the first half of the twentieth century. They were crucial to the development of radio, television, radar, sound recording and reproduction, long-distance telephone networks, and analogue and early digital computers. Although some applications had used earlier technologies such as the spark gap transmitter for radio or mechanical computers for computing, it was the invention of the thermionic vacuum tube that made these technologies widespread and practical, and created the discipline of electronics.
In the 1940s the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, more efficient, reliable and durable, and cheaper than thermionic tubes. From the mid-1960s, thermionic tubes were then being replaced with the transistor. However, the cathode-ray tube (CRT) remained the basis for television monitors and oscilloscopes until the early 21st century. Thermionic tubes still have some applications, such as the magnetron used in microwave ovens, certain high-frequency amplifiers, and amplifiers that audio enthusiasts prefer for their tube sound.
Not all electronic circuit valves/electron tubes are vacuum tubes. Gas-filled tubes are similar devices, but containing a gas, typically at low pressure, which exploit phenomena related to electric discharge in gases, usually without a heater.
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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, 2k and 4k. For more information visit http://www.PeriscopeFilm.com
