Lee de Forest

Lee DeForestDeForestDe ForestDe Forest transmitterDe Forest, LeeAmerican De Forest Wireless Telegraph CompanyDeForest CompanyDeForest Radio CompanyDeForest Wireless Telegraph CompanyDr. Lee de Forest
Lee de Forest (August 26, 1873 – June 30, 1961) was an American inventor, self-described "Father of Radio", and a pioneer in the development of sound-on-film recording used for motion pictures.wikipedia
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Audion

audion tubeAudion amplifier tubeAudion vacuum tube
His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device.
The Audion was an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest in 1906.

Triode

triode amplifiertriode tubeTriodes
His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device.
Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode (Fleming valve), the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode.

Amplifier

amplifiersamplificationelectronic amplifier
His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device.
The first practical electrical device which could amplify was the triode vacuum tube, invented in 1906 by Lee De Forest, which led to the first amplifiers around 1912.

Sound film

talkietalkiessound
Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.
In 1919, American inventor Lee De Forest was awarded several patents that would lead to the first optical sound-on-film technology with commercial application.

Radio broadcasting

radio stationradio stationsstation
Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.
The triode (mercury-vapor filled with a control grid) was patented on March 4, 1906, by the Austrian Robert von Lieben independent from that, on October 25, 1906, Lee De Forest patented his three-element Audion.

Vacuum tube

vacuum tubestubethermionic valve
His most famous invention, in 1906, was the three-element "Audion" (triode) vacuum tube, the first practical amplification device.
However amplification by a vacuum tube became practical only with Lee De Forest's 1907 invention of the three-terminal "audion" tube, a crude form of what was to become the triode.

Electronics

electronicelectronic equipmentelectronic device
Although De Forest had only a limited understanding of how it worked, it was the foundation of the field of electronics, making possible radio broadcasting, long distance telephone lines, and talking motion pictures, among countless other applications.
This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification of weak radio signals and audio signals possible with a non-mechanical device.

Northfield Mount Hermon School

Northfield Mount HermonMount Hermon SchoolNorthfield Seminary
De Forest prepared for college by attending Mount Hermon Boys' School in Mount Hermon, Massachusetts for two years, beginning in 1891.

Birth of public radio broadcasting

first public radio broadcastfirst live-performance public radio broadcastdemonstrate the technology
De Forest also used the arc-transmitter to conduct some of the earliest experimental entertainment radio broadcasts.
The birth of public radio broadcasting is credited to Lee de Forest who transmitted the world’s first public broadcast in New York City on January 13, 1910.

Josiah Willard Gibbs

Willard GibbsJ. Willard GibbsGibbs
He then completed his studies at Yale's Sloane Physics Laboratory, earning a Doctorate in 1899 with a dissertation on the "Reflection of Hertzian Waves from the Ends of Parallel Wires", supervised by theoretical physicist Willard Gibbs.
Another distinguished student was Lee De Forest, later a pioneer of radio technology.

Henry Harrison Chase Dunwoody

General H. H. C. DunwoodyHenry H. C. Dunwoody
(This problem was finally resolved with the invention of the carborundum crystal detector by another company employee, General Henry Harrison Chase Dunwoody).
In August 1902 while serving as the Signal Officer, Department of the East, Governors Island, he accepted a bid from the DeForest Wireless Telegraph Company for connecting Fort Wadsworth and Fort Hancock by wireless, replacing the telegraph cables connecting the forts and headquarters on Governor's Island which had frequently been severed by anchors and current.

Louisiana Purchase Exposition

St. Louis World's Fair1904 World's Fair1904 St. Louis World's Fair
Meanwhile, White set in motion a series of highly visible promotions for American DeForest: "Wireless Auto No.1" was positioned on Wall Street to "send stock quotes" using an unmuffled spark transmitter to loudly draw the attention of potential investors, in early 1904 two stations were established at Wei-hai-Wei on the Chinese mainland and aboard the Chinese steamer SS Haimun, which allowed war correspondent Captain Lionel James of The Times of London to report on the brewing Russo-Japanese War, and later that year a tower, with "DEFOREST" arrayed in lights, was erected on the grounds of the Louisiana Purchase Exposition in Saint Louis, Missouri, where the company won a gold medal for its radiotelegraph demonstrations.
A prototype car radio was also demonstrated by inventor Lee de Forest.

Talladega, Alabama

TalladegaTalladega, ALTalladega Center
In 1879 the elder de Forest became president of the American Missionary Association's Talladega College in Talladega, Alabama, a school "open to all of either sex, without regard to sect, race, or color", and which educated primarily African-Americans.

United Wireless Telegraph Company

American DeForest was then reorganized as the United Wireless Telegraph Company, and would be the dominant U.S. radio communications firm, albeit propped up by massive stock fraud, until its bankruptcy in 1912.
Beginning in 1902, White, promoting the work of inventor Lee de Forest, had headed a series of radio companies with dubious reputations, culminating in the American DeForest Wireless Telegraph Company.

John Vincent Lawless Hogan

John V. L. HoganHogan's Radio PicturesJohn V. Hogan
Experiments conducted with his assistant, John V. L. Hogan, convinced him that he had discovered an important new radio detector, and he quickly prepared a patent application which was filed on January 29, 1907, and received on February 18, 1908.
Hogan was born in Philadelphia, constructed his first amateur wireless station in 1902, began his career in 1906 as a laboratory assistant to Lee de Forest, and in 1907 participated in the first public demonstration of the audion tube (triode).

SS Haimun

Haimun
Meanwhile, White set in motion a series of highly visible promotions for American DeForest: "Wireless Auto No.1" was positioned on Wall Street to "send stock quotes" using an unmuffled spark transmitter to loudly draw the attention of potential investors, in early 1904 two stations were established at Wei-hai-Wei on the Chinese mainland and aboard the Chinese steamer SS Haimun, which allowed war correspondent Captain Lionel James of The Times of London to report on the brewing Russo-Japanese War, and later that year a tower, with "DEFOREST" arrayed in lights, was erected on the grounds of the Louisiana Purchase Exposition in Saint Louis, Missouri, where the company won a gold medal for its radiotelegraph demonstrations.
The recent advent of wireless telegraphy meant that reporters were no longer limited to submitting their stories from land-based offices, and The Times spent 74 days outfitting and equipping the ship, installing a De Forest transmitter aboard the ship.

Talladega College

TalladegaTalladega College Historic DistrictTornadoes
In 1879 the elder de Forest became president of the American Missionary Association's Talladega College in Talladega, Alabama, a school "open to all of either sex, without regard to sect, race, or color", and which educated primarily African-Americans.
De Forest was the father of inventor Lee De Forest.

Harriot Stanton Blatch

Harriot Eaton Stanton BlatchHarriet Stanton BlatchHarriet
In early 1909, in what may have been the first public speech by radio, de Forest's mother-in-law, Harriot Stanton Blatch, made a broadcast supporting women's suffrage.
Their first daughter, Nora Stanton Blatch Barney, continued the family tradition as a suffragist, was the first U.S. woman to earn a degree in civil engineering, and was briefly married to Lee de Forest, before entering a longer second marriage.

Phonofilm

DeForest PhonofilmDe Forest Phonofilms
In 1921 de Forest ended most of his radio research in order to concentrate on developing an optical sound-on-film process called Phonofilm.
Phonofilm is an optical sound-on-film system developed by inventors Lee de Forest and Theodore Case in the early 1920s.

Council Bluffs, Iowa

Council BluffsKanesville, IowaCouncil Bluffs, IA
Lee de Forest was born in 1873 in Council Bluffs, Iowa, the son of Anna Margaret (née Robbins) and Henry Swift DeForest.

Reginald Fessenden

Reginald Aubrey FessendenReginald A. FessendenFessenden
In 1903, Reginald Fessenden demonstrated an electrolytic detector, and de Forest developed a variation, which he called the "spade detector", claiming it did not infringe on Fessenden's patents.
Until the early-1930s, it was generally accepted that Lee de Forest, who conducted a series of test broadcasts beginning in 1907, and who was widely quoted promoting the potential of organized radio broadcasting, was the first person to transmit music and entertainment by radio.

Control grid

gridcontrolcontrol grids
He reportedly called the zig-zag control wire a "grid" due to its similarity to the "gridiron" lines on American football playing fields.
The control grid was invented by Lee De Forest, who in 1906 added a grid to the Fleming valve (thermionic diode) to create the first amplifying vacuum tube, the Audion (triode).

Heterodyne

heterodyningHeterodyne detectionfrequency shifting
Based on a notebook entry recorded at the time, de Forest asserted that, while working on the cascade amplifier, he had stumbled on August 6, 1912 across the feedback principle, which was then used in the spring of 1913 to operate a low-powered transmitter for heterodyne reception of Federal Telegraph arc transmissions.
A stable yet inexpensive local oscillator was not available until Lee de Forest invented the triode vacuum tube oscillator.

Sheffield Scientific School

Yale Scientific SchoolScientific SchoolSheffield Chemical Laboratory
In 1893, he enrolled in a three-year course of studies at Yale University's Sheffield Scientific School in New Haven, Connecticut, on a $300 per year scholarship that had been established for relatives of David de Forest.

Tri-Ergon

Hans Vogt
In 1919 he filed the first patent for the new system, which improved upon earlier work by Finnish inventor Eric Tigerstedt and the German partnership Tri-Ergon.
The Tri-Ergon process involved recording sound onto film using the "variable density" method, used by Movietone and Lee De Forest's Phonofilm, rather than the "variable area" method later used by RCA Photophone.