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Karl Ferdinand Braun (1850 – 1918), invented the cathode ray tube and shared a Noble Prize with Marconi for work on wireless telegraphy

Telegraphy and television

Two fields of achievement for one pioneer

If things had happened differently, we might now be watching the screens of “electrical telescopes” in our living rooms. That was one of the terms coined a century ago for what, today, we call television sets. But when was the word “television” first used, and by whom? We asked that question at the end of last month’s Pioneers’ Page. In fact, it was as far back as 1900 that the word “télévision” first appeared, in a paper* (in French) by the Russian physicist Constantin Perskyi, presented at the first International Electricity Congress that was held alongside the Great Exhibition in Paris.

Perskyi was Professor of Electricity at the Artillery Academy in Saint Petersburg. His lecture in Paris simply reviewed the progress that had been made up to then in achieving the dream of viewing things at a distance. The debate in Paris at the “Palace of Electricity” was chiefly concerned with physics, rather than with the possible technology of television. Nevertheless, crucial steps had already been taken towards creating a practical device. One of the most important of these was the invention of the cathode ray tube (CRT).

The tube in the box

By the middle of the nineteenth century, it had been noticed that when a strong electric current was passed from one wire to another sealed within a glass tube, glowing light was produced inside that could be manipulated by waving a magnet over its surface. And when air was pumped out to create a vacuum, a patch of fluorescence appeared on the glass. This forerunner of the neon sign made a wonderfully showy effect, but in the 1870s it was also developed into a useful scientific instrument (the Crookes Tube) by Briton William Crookes, who wanted to investigate how electricity interacts with rarified gases. In 1876, the German physicist Eugen Goldstein gave the name “cathode rays” to the radiation that causes the fluorescence.

It was not until two decades later, in 1897, that J.J. Thomson at the University of Cambridge used the Crookes Tube in first discovering sub-atomic particles — electrons — and demonstrated that cathode rays are the same thing: a stream of what he called “corpuscles of negative electricity.” In the same year, the “cathode ray indicator tube” was invented by Karl Ferdinand Braun, of Germany. Unlike earlier vacuum tubes, the Braun Tube allowed precise control of a narrow particle beam (using alternating voltage) that could trace patterns onto the fluorescent end of the device. This was initially developed as an oscillograph, but was also the origin of the CRT for the televisions and computer monitors of the future.

Diagram of a cathode ray tube

 

Source: Theresa Knott

 

Long-distance messages

Thomson received the Nobel Prize in physics for his work in 1906 — the year, too, that ITU’s Radio Regulations were born, governing a field in which Braun was also distinguished. In 1909, he shared a Nobel Prize with Guglielmo Marconi, for their contributions to the development of radio. Through introducing a closed circuit of oscillation, Braun overcame the “dampening” effect that weakened Marconi’s original design for wireless telegraphy. The critical improvements that he made achieved a tenfold extension of telegraphy’s range to some 100 kilometres, as well as adding the capacity to target transmissions more narrowly, by means of inclined beam antennae. This meant that people could send radio messages in greater privacy — a factor of major importance to business users, for example.

 


Deutsches Museum

  Model of a 1906 cathode ray tube, designed by Braun

The achievement was recognized by Hans Hildebrand, Secretary of the Royal Swedish Academy, in the speech he gave upon presenting Braun with a Nobel Prize. Describing Braun’s work as “inspired”, Hildebrand noted that it was only through the German scientist’s efforts that long distance telegraphy had become possible, and “that the magnificent results in the use of wireless telegraphy have been attained in recent times.”

Just after the outbreak of the First World War, Braun travelled to New York to attend a court case over a patent claim. He was prevented from returning to Germany when the United States entered the war, and because he was by then seriously ill. He died in New York in April 1918, at the age of 67. The cathode ray tube that he invented has remained the technology upon which television receivers are based — until very recently. Nowadays, flat-screen plasma or liquid-crystal display (LCD) televisions are rapidly taking over. And the word “television,” first heard more than a century ago, is now understood in almost every country of the world — in much the same way as the technology itself pervades our lives.

*  “Télévision au moyen de l’électricité
Exposition universelle internationale de 1900,
Congrès international de l’électricité (Paris, 18–25 August 1900).

 

Question for next month

Who was the famous engineer who created not only the first video recording system...
...but also special, damp-proof socks?

 

 

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