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Lee De Forest: Biography, Inventions & Achievements

Instructor: Leslie McMurtry
In this lesson, we'll be looking at the life, career, and inventions of prolific inventor and sound innovator Lee De Forest. We'll examine the driving forces that led him to experiment with sound technology at the beginning of the twentieth century, his world-changing invention of the three- element tube, and his frequent entanglements with US patent law.

Early Life

Lee De Forest was a prolific inventor, receiving more than 300 patents in his lifetime. His life was also characterized by lawsuits in order to gain patent control over his inventions.

De Forest was born in Council Bluffs, Iowa, in 1873. Both he and Thomas Edison were from comfortable middle-class Midwestern backgrounds. His father, a Congregational minister, became president of Talladega College in Alabama. In 1893, De Forest visited the Columbia Exposition in Chicago where he first became interested in the inventions of Nikola Tesla. That year, De Forest was also able to get a scholarship to Yale University to study engineering. He had to convince his father to let him go into this career, writing, I intend to be a machinist and inventor because I have great talents in that direction. In this I think you will agree with me. If this be so, why not allow me to so study as to best prepare myself for that profession? He completed his doctorate in 1899 and started work at Western Electric, Chicago, Illinois while tinkering on the side.

In 1901, he moved to New York City, New York, where he used the spark gap responder system he had created (which was faster than Guglielmo Marconi's similar device) and tested it in Chicago in reporting on yacht races. Marconi is often considered to be the inventor of the radio, having completed early experiments in the 1890s and popularizing the communication system's possibilities.

Abraham White, a wealthy investor, helped establish the De Forest Telegraph Company in 1902. In 1903, De Forest visited Reginald Fessenden, a rival inventor, who had developed the electrolytic detector. Afterwards, the De Forest Telegraph Company developed a variation on this. Based on this new component, De Forest won prizes at the St Louis World's Fair in 1904. His subsequent radiotelegraph stations were purchased by the US Navy. However, Fessenden believed that De Forest had stolen the electrolytic detector from him and filed suit for patent infringement.

Invention Examples

De Forest three-element vacuum tube c.1910
Three-element tube

Invention of the Three-Element Tube (Audion)

In 1905, blocked by Fessenden, De Forest turned to experimentation that ultimately led to the development of the three-element tube (using anode, cathode, and electrode), one of the most important inventions of the twentieth century and the basic design behind all of our electronic devices. De Forest called this the Audion. The innovation of this device and those that followed was in detecting, amplifying and transmitting radio signals. The three-element tube served as an oscillator (a device which generates electric currents, like sine waves) and when scaled up and used as a detector in a radio receiver, the device created an increase in sensitivity to incoming signals.

In 1911, De Forest moved to California and began working for the Federal Telegraph Company. Between 1913 and 1917, De Forest was able to sell his patent for the Audion (including the three-element tube) to AT&T, further accelerating the development of radio communications. In 1916, De Forest set up his own radio station in the Bronx, New York. He reported on the presidential election that year in November, though unfortunately when the station signed off the air at 11 pm, it broadcast that the new president was Charles Evans Hughes. In fact, when all votes were counted, the president was Woodrow Wilson, re-elected for a second term.

Nevertheless, De Forest had a great belief in radio's qualities, writing, 'He alone the radio innovator hears the etheric 'call of the wild,' and when it speaks to him in the well-known accents of a distant friend, or when music of silent spirits, coming in from nowhere, sings to him the strains of some well loved earthly melody, his wonder grows, and he trembles at the weirdness of it all.'

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