Lee de forest biography of michael

Lee de Forest invented the Talking Motion Picture. Lee de Forest, , was an inventor and scholar who made significant contributions to the science of electronic communications during the first three decades of the Twentieth Century. He held numerous patents on the technology of radio, television and film. Have a question about Lee de Forest?

He had a weak idea of the power of silent cinema and the importance of stars. De Forest's Phonofilm shorts of the early s were static once highlighting the speechifying of Calvin Coolidge. The public went ape for Al Jolson and the phonograph disk—driven Vitaphone system; Adams suggests the public and the exhibitors weren't as impressed by de Forest's "laboratory experiments posing as cinema.

As a longtime teacher, Adams finds the anecdotes that make de Forest relevant. His courtship via radio code of his first wife Lucille "might be compared to the text messaging of today. The discursions are worth the trip, too. We learn the tidbit that the very early narrative film The Great Train Robbery was followed by what is likely the first sequel in movie history: The Little Train Robbery , with an Our Gang—like group of banditos robbing a miniature train.

Lee de forest biography of michael

Policies and ethics. Skip to main content. Home Book. Download book EPUB. Lee de Forest. Download book PDF. Tax calculation will be finalised at checkout. Licence this eBook for your library. Learn about institutional subscriptions. The life-long inventor, Lee de Forest invented the three-element vacuum tube used between and as a detector, amplifier, and oscillator of radio waves.

However, he also admitted that "I have arrived as yet at no completely satisfactory theory as to the exact means by which the high-frequency oscillations affect so markedly the behavior of an ionized gas. In late , de Forest made a breakthrough when he reconfigured the control electrode, moving it from outside the tube envelope to a position inside the tube between the filament and the plate.

He called the intermediate electrode a grid , reportedly due to its similarity to the "gridiron" lines on American football playing fields. Hogan , convinced him that he had discovered an important new radio detector. He quickly prepared a patent application which was filed on January 29, , and received U. Because the grid-control Audion was the only configuration to become commercially valuable, the earlier versions were forgotten, and the term Audion later became synonymous with just the grid type.

It later also became known as the triode. The grid Audion was the first device to amplify, albeit only slightly, the strength of received radio signals. However, to many observers it appeared that de Forest had done nothing more than add the grid electrode to an existing detector configuration, the Fleming valve , which also consisted of a filament and plate enclosed in an evacuated glass tube.

De Forest passionately denied the similarly of the two devices, claiming his invention was a relay that amplified currents, while the Fleming valve was merely a rectifier that converted alternating current to direct current. For this reason, de Forest objected to his Audion being referred to as "a valve". The U. In contrast, Marconi admitted that the addition of the third electrode was a patentable improvement, and the two sides agreed to license each other so that both could manufacture three-electrode tubes in the United States.

De Forest's European patents had lapsed because he did not have the funds needed to renew them. Because of its limited uses and the great variability in the quality of individual units, the grid Audion would be rarely used during the first half-decade after its invention. In , John V. Hogan reported that "The Audion is capable of being developed into a really efficient detector, but in its present forms is quite unreliable and entirely too complex to be properly handled by the usual wireless operator.

In May , the Radio Telephone Company and its subsidiaries were reorganized as the North American Wireless Corporation, but financial difficulties meant that the company's activities had nearly come to a halt. De Forest moved to San Francisco, California, and in early took a research job at the Federal Telegraph Company , which produced long-range radiotelegraph systems using high-powered Poulsen arcs.

One of de Forest's areas of research at Federal Telegraph was improving the reception of signals, and he came up with the idea of strengthening the audio frequency output from a grid Audion by feeding it into a second tube for additional amplification. He called this a "cascade amplifier", which eventually consisted of chaining together up to three Audions.

At this time the American Telephone and Telegraph Company was researching ways to amplify telephone signals to provide better long-distance service, and it was recognized that de Forest's device had potential as a telephone line repeater. It was found that de Forest's "gassy" version of the Audion could not handle even the relatively low voltages used by telephone lines.

Owing to the way he constructed the tubes, de Forest's Audions would cease to operate with too high a vacuum. However, careful research by Dr. Harold D. With these changes the Audion evolved into a modern electron-discharge vacuum tube, using electron flows rather than ions. Irving Langmuir at the General Electric Corporation made similar findings, and both he and Arnold attempted to patent the "high vacuum" construction, but the U.

Supreme Court ruled in that this modification could not be patented. De Forest had hoped for a higher payment, but was again in bad financial shape and was unable to bargain for more. Radio Telephone Company officials had engaged in some of the same stock selling excesses that had taken place at American DeForest, and as part of the U. Their trials took place in late , and while three of the defendants were found guilty, de Forest was acquitted.

The Radio Telephone Company began selling "Oscillion" power tubes to amateurs, suitable for radio transmissions. The company wanted to keep a tight hold on the tube business, and originally maintained a policy that retailers had to require their customers to return a worn-out tube before they could get a replacement. This style of business encouraged others to make and sell unlicensed vacuum tubes which did not impose a return policy.

Cunningham of San Francisco, whose Audio Tron tubes cost less but were of equal or higher quality. The de Forest company sued Audio Tron Sales, eventually settling out of court. However, it also became known for the poor quality of its vacuum tubes, especially compared to those produced by major industrial manufacturers such as General Electric and Western Electric.

Beginning in , there was increased investigation of vacuum-tube capabilities, simultaneously by numerous inventors in multiple countries, who identified additional important uses for the device. These overlapping discoveries led to complicated legal disputes over priority, perhaps the most bitter being one in the United States between de Forest and Edwin Howard Armstrong over the discovery of regeneration also known as the "feedback circuit" and, by de Forest, as the "ultra-audion".

Beginning in Armstrong prepared papers and gave demonstrations that comprehensively documented how to employ three-element vacuum tubes in circuits that amplified signals to stronger levels than previously thought possible, and that could also generate high-power oscillations usable for radio transmission. In late Armstrong applied for patents covering the regenerative circuit , and on October 6, U.

With an eye to increasing the value of the patent portfolio that would be sold to Western Electric in , beginning in de Forest filed a series of patent applications that largely copied Armstrong's claims, in the hopes of having the priority of the competing applications upheld by an interference hearing at the patent office. 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, , across the feedback principle, which was then used in the spring of to operate a low-powered transmitter for heterodyne reception of Federal Telegraph arc transmissions.

However, there was also strong evidence that de Forest was unaware of the full significance of this discovery, as shown by his lack of follow-up and continuing misunderstanding of the physics involved. In particular, it appeared that he was unaware of the potential for further development until he became familiar with Armstrong's research.

De Forest was not alone in the interference determination—the patent office identified four competing claimants for its hearings, consisting of Armstrong, de Forest, General Electric's Langmuir, and a German, Alexander Meissner, whose application would be seized by the Office of Alien Property Custodian during World War I. The subsequent legal proceedings become divided between two groups of court cases.

The first court action began in January when Armstrong, with Westinghouse, which purchased his patent, sued the De Forest Company in district court for infringement of patent 1,, However, a second series of court cases, which were the result of the patent office interference proceeding, had a different outcome. The interference board had also sided with Armstrong, and de Forest appealed its decision to the District of Columbia district court.

On May 8, , that court concluded that the evidence, beginning with the notebook entry, was sufficient to establish de Forest's priority. Now on the defensive, Armstrong's side tried to overturn the decision, but these efforts, which twice went before the U. Supreme Court, in and , were unsuccessful. This judicial ruling meant that Lee de Forest was now legally recognized in the United States as the inventor of regeneration.

However, much of the engineering community continued to consider Armstrong to be the actual developer, with de Forest viewed as someone who skillfully used the patent system to get credit for an invention to which he had barely contributed. Following the Supreme Court decision, Armstrong attempted to return his Institute of Radio Engineers present-day Institute of Electrical and Electronics Engineers Medal of Honor, which had been awarded to him in "in recognition of his work and publications dealing with the action of the oscillating and non-oscillating audion", but the organization's board refused to let him, stating that it "strongly affirms the original award".

De Forest regularly responded to articles which he thought exaggerated Armstrong's contributions with animosity that continued even after Armstrong's suicide. Following the publication of Carl Dreher 's "E. Armstrong, the Hero as Inventor" in the August Harper's magazine, de Forest wrote the author, describing Armstrong as "exceedingly arrogant, brow beating, even brutal In the summer of , the company received an Experimental license for station 2XG , [ 40 ] located at its Highbridge laboratory.

In late , de Forest renewed the entertainment broadcasts he had suspended in , now using the superior capabilities of vacuum-tube equipment. These broadcasts were also used to advertise "the products of the DeForest Radio Co. About 2, listeners heard The Star-Spangled Banner and other anthems, songs, and hymns. With the entry of the United States into World War I on April 6, , all civilian radio stations were ordered to shut down, so 2XG was silenced for the duration of the war.

The ban on civilian stations was lifted on October 1, , and 2XG soon renewed operation, with the Brunswick-Balke-Collender company now supplying the phonograph records. A new station, 6XC , was established as "The California Theater station", which de Forest later stated was the "first radio-telephone station devoted solely" to broadcasting to the public.

Later that year a de Forest associate, Clarence "C. In , de Forest ended most of his radio research in order to concentrate on developing an optical sound-on-film process called Phonofilm. In 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.

Phonofilm recorded the electrical waveforms produced by a microphone photographically onto film, using parallel lines of variable shades of gray, an approach known as "variable density", in contrast to "variable area" systems used by processes such as RCA Photophone. When the movie film was projected, the recorded information was converted back into sound, in synchronization with the picture.