Karl Ferdinand Braun

For the German politician and writer, seeKarl Braun (politician).

Karl Ferdinand Braun
Braun in 1909
Born	(1850-06-06)6 June 1850 Fulda,Electorate of Hesse
Died	20 April 1918(1918-04-20)(aged 67) Brooklyn,New York City,U.S.
Alma mater	University of Marburg University of Berlin
Known for	Crystal detector Inductively coupled transmitter Phased array Braun tube Le Chatelier–Braun principle
Awards	Nobel Prize in Physics(1909)
Scientific career
Fields	Physics
Institutions	University of Karlsruhe University of Marburg University of Strassburg University of Tübingen University of Würzburg
Doctoral advisor	August Kundt Georg Hermann Quincke
Doctoral students	Leonid Isaakovich Mandelshtam Albert Schweizer

Ferdinand Braun's birthplace inFulda

24 September 1900: Bargman, Braun and telegraphist at wireless station inHeligoland

Karl Ferdinand Braun(German pronunciation:[ˈfɛʁdinantˈbʁaʊn];6 June 1850 – 20 April 1918) was a Germanelectrical engineer,inventor,physicistand Nobel laureate inPhysics.Braun contributed significantly to the development of theradio,when he invented thephased arrayantenna in 1905,which led to the development ofradar,smart antennas,MIMOand thetelevisionby building the firstcathode-ray tube.Braun also built the firstsemiconductor.

He shared the 1909 Nobel Prize in Physics withGuglielmo Marconi"for their contributions to the development of wireless telegraphy", was a founder ofTelefunken,one of the pioneering communications and television companies,and has been both called the "father of television" (shared with inventors likePaul Gottlieb Nipkow), "great grandfather of every semiconductor ever manufactured"and the co-father of the radio telegraphy, together with Marconi.

Biography

Braun was born inFulda,Germany, and educated at theUniversity of Marburgand received a PhD from theUniversity of Berlinin 1872. In 1874, he discovered in Leipzig while he was working there as a secondary school teacher in theThomasschule,that a point-contactmetal–semiconductor junctionrectifiesalternating current.He became director of the Physical Institute and professor ofphysicsat theUniversity of Strassburgin 1895.

In 1897, he built the firstcathode-ray tube(CRT) and cathode-ray tubeoscilloscope.The CRT became the cornerstone in developing fully electronic television, being a part of every TV, computer and any other screen set up till the introduction of the LCD screen at the end of the 20th century.It is still mostly called the "Braun tube" in German-speaking countries (Braunsche Röhre) and other countries such as Korea (브라운관:Buraun-kwan) and Japan (ブラウン quản:Buraun-kan).

During thedevelopment of radio,he also worked onwireless telegraphy.In 1897, Braun joined the line of wireless pioneers.His major contributions were the introduction of a closed tuned circuit in the generating part of the transmitter, its separation from the radiating part (the antenna) by means of inductive coupling, and later on the usage of crystals for receiving purposes. Around 1898, he invented acrystal detector.Wireless telegraphy claimed Dr. Braun's full attention in 1898, and for many years after that he applied himself almost exclusively to the task of solving its problems. Dr. Braun had written extensively on wireless subjects and was well known through his many contributions to the Electrician and other scientific journals.In 1899, he would apply for the patentWireless electro transmission of signals over surfaces.Also in 1899, he is said to have applied for a patent onElectro telegraphy by means of condensers and induction coils.

Pioneers working on wireless devices eventually came to a limit of distance they could cover. Connecting the antenna directly to the spark gap produced only a heavily damped pulse train. There were only a few cycles before oscillations ceased. Braun's circuit afforded a much longer sustained oscillation because the energy encountered less losses swinging between coil and Leyden Jars. And by means of inductive antenna coupling the radiator was better matched to the generator. The resultant stronger and less bandwidth consuming signals bridged a much longer distance.

Braun invented thephased arrayantenna in 1905. He described in his Nobel Prize lecture how he carefully arranged three antennas to transmit a directional signal.This invention led to the development ofradar,smart antennas,andMIMO.

Braun's British patent on tuning was used by Marconi in many of his tuning patents.Guglielmo Marconiused Braun's patents (among others). Marconi would later admit to Braun himself that he had "borrowed"portions of Braun's work.In 1909, Braun shared the Nobel Prize for physics with Marconi for "contributions to the development ofwireless telegraphy".The prize awarded to Braun in 1909 depicts this design. Braun experimented at first at the University of Strasbourg. Not before long he bridged a distance of 42 km to the city of Mutzig. In spring 1899, Braun, accompanied by his colleagues Cantor and Zenneck, went to Cuxhaven to continue their experiments at the North Sea. On 24 September 1900 radio telegraphy signals were exchanged regularly with the island ofHeligolandover a distance of 62 km. Light vessels in the river Elbe and a coast station atCuxhavencommenced a regular radio telegraph service.

Braun went to the United States at the beginning ofWorld War I(before the U.S. had entered the war) to be a witness for the defense in a lawsuit regarding a patent claim by theMarconi Corporationagainst the wireless station of Telefunken atSayville, New York.After the US entered the war, Braun wasdetained,but could move freely withinBrooklyn,New York. Braun died in his house in Brooklyn, before the war ended in 1918.

SID Karl Ferdinand Braun Prize

In 1987 theSociety for Information Displaycreated the Karl Ferdinand Braun Prize, awarded for an outstanding technical achievement in display technology.

Patents

• U.S. Patent 0,750,429, Wireless Electric Transmission of Signals Over Surfaces
• U.S. Patent 0,763,345, Means for Tuning and Adjusting Electric Circuits

See also

• History of radio
• Invention of radio
• Edouard Branly

References

Footnotes

General

• K.F. Braun: "On the current conduction in metal sulphides (title translated from German into English)",Ann. Phys. Chem.,153 (1874), 556. (In German) An English translation can be found inSemiconductor Devices: Pioneering Papers,edited by S.M. Sze, World Scientific, Singapore, 1991, pp. 377–380.
• Keller, Peter A.:The Cathode-Ray Tube: Technology, History, and Applications.New York: Palisades Press, 1991.ISBN0-9631559-0-3.
• Keller, Peter A.: "The 100th Anniversary of the Cathode-Ray Tube,"Information Display,Vol. 13, No. 10, 1997, pp. 28–32.
• F. Kurylo,Ferdinand Braun Leben und Wirken des Erfinders der Braunschen Röhre Nobelpreis 1909,Munich: Moos Verlag, 1965. (In German)

External links

• Media related toKarl Ferdinand Braunat Wikimedia Commons
• Karl Ferdinand Braunat theMathematics Genealogy Project
• Karl Ferdinand Braunon Nobelprize.orgincluding the Nobel Lecture, 11 December 1909Electrical Oscillations and Wireless Telegraphy
• Naughton, Russell, "Karl Ferdinand Braun, Dr: 1850 – 1918".
• "Karl Ferdinand Braun".Biographies of Famous Electrochemists and Physicists Contributed to Understanding of Electricity.
• "Karl Ferdinand Braun, 1850–1918".(German) (Englishtranslation)
• The Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik Berlin, Germany
• Alfred Thomas StoryA Story of Wireless Telegraphy.D. Appleton and company 1904