A D V E N T U R E S   in   C Y B E R S O U N D

Lee De Forest, b. Council Bluffs, Iowa, Aug. 26, 1873, d. June 30, 1961, was a pioneer of wireless telegraphy in the United States. A prolific inventor, he was granted more than 300 patents in the fields of wireless telegraphy, radio, wire telephone, sound-on-film, picture transmission, and television. He is most widely known for introducing a third electrode into the two-electrode electron tube (the diode), creating the Triode, or Audion tube, which could amplify radio signals and generate oscillations; these two functions had many important applications.

Frank G. Spreadbury

Source: The New Grolier Multimedia Encyclopedia

The broadcasting of sound, or radio broadcasting, began when Lee De Forest invented the Audion tube. His invention changed the living habits of millions; yet he made almost nothing from it.

Lee De Forest was born in Council Bluffs, Iowa, on Aug. 26, 1873. His father, a Congregationalist minister, became head of Talladega College for Negroes in Alabama in 1881. The white community was unfriendly to Lee and his family, and so young Lee made few friends. To fill his lonely hours, he turned to science. By the age of 13 he had invented several mechanical gadgets. A scholarship enabled him to attend the Sheffield Scientific School at Yale University. Some classmates called him the "homeliest and nerviest student in school." He worked hard and earned his doctor of philosophy degree in 1899.

While he earned his living at various jobs, he steadily experimented after hours. One problem especially challenged him. Marconi had already sent the "dot-dash" of the telegraph code through the air by radio waves, but no one had found a way to broadcast music or speech. Experimenting with Fleming's vacuum tube, De Forest introduced a third part--a grid between the filament and the plate. He patented this Audion tube in 1907 and broadcast a live Metropolitan Opera performance of Enrico Caruso in 1910. Radio broadcasting was born, but the public was not interested. Discouraged, De Forest sold the rights to the tube to a telephone company.

In the following years he took out more than 300 patents on radio and other electronic devices. One invention was phonofilm, a forerunner of sound-track motion-picture film. In 1923 he showed the first public "talking" movie. Wider recognition came to him in his later years, but he was bitter about the financial gains made by others on his inventions. He died on June 30, 1961, in Hollywood, California.

Source: Compton's Encyclopaedia

Lee De Forest (b. Aug. 26, 1873, Council Bluffs, Iowa, U.S.--d. June 30, 1961, Hollywood), American inventor of the Audion vacuum tube, which made possible live radio broadcasting and became the key component of all radio, telephone, radar, television, and computer systems before the invention of the transistor in 1947.

Life

De Forest was the son of a Congregational minister. His father moved the family to Alabama and there assumed the presidency of the nearly bankrupt Talladega College for Negroes. Ostracized by citizens of the white community who resented his father's efforts to educate blacks, Lee made his friends from among the black children of the town and, together with his brother and sister, spent a happy although sternly disciplined childhood in this rural community.

As a child he was fascinated with machinery and was often excited when hearing of the many technological advances during the late 19th century. By the age of 13 he was an enthusiastic inventor of mechanical gadgets such as a miniature blast furnace and locomotive, and a working silverplating apparatus.

His father had planned for him a career in the clergy, but Lee insisted on science and, in 1893, enrolled at the Sheffield Scientific School of Yale University, one of the few institutions in the United States then offering a first-class scientific education. Frugal and hardworking, he supplemented his scholarship and the slim allowance provided by his parents by working at menial jobs during his college years, and, despite a not too distinguished undergraduate career, he went on to earn the Ph.D. in physics in 1899.

By this time he had become interested in electricity, particularly the study of electromagnetic wave propagation, then being pioneered chiefly by the German Heinrich Rudolf Hertz and the Italian Guglielmo Marconi. De Forest's doctoral dissertation on the "Reflection of Hertzian Waves from the Ends of Parallel Wires" was possibly the first doctoral thesis in the United States on the subject that was later to become known as radio.

His first job was with the Western Electric Company in Chicago, where, beginning in the dynamo department, he worked his way up to the telephone section and then to the experimental laboratory. While working after-hours on his own, he developed an electrolytic detector of Hertzian waves. The device was modestly successful, as was an alternating-current transmitter that he designed.

In 1902 he and his financial backers founded the De Forest Wireless Telegraph Company. In order to dramatize the potential of this new medium of communication, he began, as early as 1902, to give public demonstrations of wireless telegraphy for businessmen, the press, and the military.

The invention of the Audion tube

A poor businessman and a poorer judge of men, De Forest was defrauded twice by his own business partners. By 1906 his first company was insolvent, and he had been squeezed out of its operation. But in 1907 he patented a much more promising detector (developed in 1906) which he called the "Audion"; it was capable of more sensitive reception of wireless signals than were the electrolytic and Carborundum types then in use.

It was a thermionic grid-triode vacuum tube, a three-element electronic "valve" similar to a two-element device patented by the Englishman Sir John Ambrose Fleming in 1905. The same year De Forest was able to broadcast experimentally both speech and music to the general public in the New York City area. (see also Index: thermionic power converter)

A second company, the De Forest Radio Telephone Company, began to collapse in 1909, again because of some of his partners. In the succeeding legal confusion, De Forest was indicted in 1912 but later acquitted of federal charges of using the mails to defraud by seeking to promote a "worthless device", the Audion tube.

In 1910 he broadcast a live performance by Enrico Caruso at the Metropolitan Opera in order to further popularize the new medium. In 1912 De Forest conceived the idea of "cascading" a series of Audion tubes so as to amplify high-frequency radio signals far beyond what could be accomplished by merely increasing the voltage on a single tube.

He fed the output from the plate of one tube, through a transformer to the grid of a second, and the output of the second tube's plate to the grid of a third, and so forth, thereby allowing for an enormous amplification of a signal that was originally very weak. This was an essential development for both radio and telephonic long-distance communication.

He also discovered in 1912 that by feeding part of the output of his triode vacuum tube back into its grid, he could cause a self-regenerating oscillation in the circuit. The signal from this circuit, when fed to an antenna system, was far more powerful and effective than that of the crude transmitters then generally employed and, when properly modulated, was capable of transmitting speech and music. When appropriately modified, this single invention was capable of either transmitting, receiving, or amplifying radio signals.

Throughout De Forest's lifetime the originality of his more important inventions was hotly contested, by both scientists and patent attorneys. In time, realizing that he could not succeed in business or manufacturing, he reluctantly sold his patents to major communications firms for commercial development. Some of the most important of these sales were made at very low prices to the American Telephone & Telegraph Company, which used the Audion as an essential amplification component for long-distance repeater circuits.

Other inventions

In 1920 he began to work on a practical system for recording and reproducing sound motion pictures. He developed a sound-on-film optical-recording system called Phonofilm and demonstrated it in theatres between 1923 and 1927. Although basically correct in principle, its operating quality was poor, and he found himself unable to interest film producers in its possibilities. Ironically, within a few years' time the motion-picture industry converted to talking pictures by using a sound-on-film process similar to that of De Forest.

During the 1930s De Forest developed Audion-diathermy machines for medical applications and, during World War II, conducted military research for Bell Telephone Laboratories. Although bitter over the financial exploitation of his inventions by others, he was widely honoured as the "father of radio" and the "grandfather of television." He was supported strongly but unsuccessfully for the Nobel Prize for Physics.

Although he worked for many organizations during his lifetime, De Forest was fundamentally an individualist and produced most of his inventions as a free-lance worker. A complex and private man, De Forest was assailed by self-doubts, indecision, and egocentricity. Divorced twice, his third marriage, to Marie Mosquini, was a happy one and endured from 1930 until his death

Bibliography

Israel E. Levine, Electronics Pioneer: Lee De Forest (1964)

W. Rupert Maclaurin, Invention and Innovation in the Radio Industry (1949, reprinted 1975)

Source: Britannica On Line

In 1907, US physicist and inventor Lee de Forest (1873-1961) patents the triode which, as the name suggests, added a third electrode to the diode, in the form of a wire-mesh 'grid'. (An Austrian physicist named Robert von Lieben (1878-1914) discovered the triode valve in 1906 but his work was never exploited. Von Lieben died in the war and De Forest got the lion's share of the credit.)

De Forest's 'Audion' valve is initially regarded as only a very sensitive detector of radio waves, and for five years its potential as an amplifier and oscillator is overlooked. However its value is eventually appreciated by the telephone and telegraph networks and De Forest ends up selling what he called his 'glass bottle full of nothing' to the American Telephone and Telegraph Company for $390,000.

De Forest has previously been working on solutions to the rapid transmission of wireless signals; his system is used in 1904 for the first wireless news report - of the Russo-Japanese War. De Forest set up his own wireless telegraph company but nearly is bankrupt twice. He is also prosecuted for attempting to use the US Mail to defraud, for marketing his 'Audion' valve; at that time it is considered worthless by the authorities.

In 1910, De Forest stages the first radio broadcast in history from the Metropolitan Opera House in New York. In 1916, he sets up his own radio station and begins regular broadcasts. He is known as the 'father of radio' in the USA. In 1923, he demonstrates an early poor-quality system of motion pictures carrying a soundtrack called phonofilm. He patents more than 300 inventions, the last one at the age of 84.

Source: http://www.cequel.co.uk/acclarke/shc.html

Lee De Forest (August 26, 1873-June 30, 1961), for whom the Lee Project is named, is often referred to as the "Father of Radio" (itself the title of his 1950 autobiography). An alumnus of the Mount Hermon School for Boys he is remembered as a brilliant inventor and promoter whose work launched a new era in electronics.

In 1906, De Forest invented the triode or "audion tube", a vacuum or electron tube with 3 electrodes (instead of the 2 electrodes of the previously ubiquitous vacuum diode). The triode served the amplifying and switching functions which would later be performed by the transistor, and made numerous electronic circuits commercially feasible. (Initially, the most prominent among these was the radio, which, thanks to the triode, could be affordably manufactured.)

In the same year, De Forest married Nora Stanton, an accomplished engineer and the grand-daughter of the famous women's rights activist Elizabeth Cady Stanton.

De Forest, seeing the potential of radio technology, became a major promoter of its adoption, setting up dramatic public demonstration and attempting to raise capital. In this role he came under some criticism from those who doubted that radio would ever catch on; his fundraising efforts even got him in legal trouble. At his famous trial in 1913, the District Attorney charged that...

"De Forest has said in many newspapers and over his signature that it would be possible to transmit human voice across the Atlantic before many years. Based on these absurd and deliberately misleading statements, the misguided public ... has been persuaded to purchase stock in his company"

Lee De Forest's triode was essential to the development of practical radios, telephones, televisions, radars, and computers (the famous "vacuum tubes" of the original computers being descendents of De Forest's audion tubes). As such, the triode ranks among the most useful and influential inventions in history.

Although the triode has been superseded by the solid-state transistor, which uses ultra-thin slices of semiconductors instead of a bulky glass tube, De Forest's insights clearly demonstrated for the first time the potential of wireless communications and were a tremendous boon to fundamental electronics research.