Braun was a co-founder ofTelefunken, one of the pioneering communications and television companies.[6] He has been called the "father of television" (shared with inventors likePaul Nipkow), the "great-grandfather of every semiconductor ever manufactured",[7] and a co-father ofradiotelegraphy, together with Marconi,[8][9][10][11] laying the foundation for all modernwireless systems.[12]
In 1897, Braun joined the line ofwireless pioneers.[15][16] His major contributions to thedevelopment of radio were the introduction of a closed tuned circuit in the generating part of thetransmitter, its separation from the radiating part (theantenna) by means ofinductive coupling, and later on the usage of crystals for receiving purposes. Around 1898, he invented acrystal detector[citation needed].Wireless telegraphy claimed his full attention in 1898, and for many years after that he applied himself almost exclusively to the task of solving its problems. He had written extensively on wireless subjects and was well known through his many contributions toThe Electrician and other scientific journals.[17] In 1899, he applied for the patentWireless electro transmission of signals over surfaces.[18] Also in 1899, he is said to have applied for a patent onElectro telegraphy by means of condensers and induction coils.[citation needed]
Pioneers working on wireless devices eventually came to a limit of distance they could cover; connecting the antenna directly to thespark 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 andLeyden jars. And by means of inductive antenna coupling the radiator was better matched to thegenerator. The resultant stronger and less bandwidth consuming signals bridged a much longer distance.
Braun's British patent on tuning was used byGuglielmo Marconi in many of his tuning patents. Marconi used Braun's patents (among others). Marconi would later admit to Braun himself that he had "borrowed" portions of Braun's work.[citation needed] In 1909, Braun and Marconi were jointly awarded theNobel Prize in Physics "in recognition of their contributions to the development of wireless telegraphy"; the prize awarded to Braun depicts this design. He experimented initially at the University of Strassburg, not long before he bridged a distance of 42 km toMutzig. In spring 1899, Braun, accompanied by his colleagues Cantor and Zenneck, went toCuxhaven to continue their experiments at the North Sea. On 24 September 1900, radio telegraphy signals were exchanged regularly with the island ofHeligoland over a distance of 62 km. Light vessels in the riverElbe and a coast station at Cuxhaven commenced a regular radio telegraph service.
In 1914, Braun went toNew York in the United States to be a witness for the defense in a lawsuit regarding a patent claim by theMarconi Company against Telefunken's wireless station inSayville. He was a Lutheran[20][21]
In 1874, Braun discovered the asymmetric conduction properties of certain materials, which became the foundation for the point-contactrectifier. This discovery showed that certainmetal-semiconductor junctions could conduct electricity more easily in one direction than the other, a crucial property fordiodes.[24]
Braun's work with semiconductors led to the development of the firstpoint-contact diode, often credited as a basic semiconductor device that allowed the rectification ofalternating current intodirect current. This is important because it was one of the first real-world applications of semiconducting materials, paving the way for futuresemiconductor devices that would later evolve into modern diodes,transistors, and other semiconductor technology.
Braun's discoveries were instrumental in the early development ofelectronics and helped lay the groundwork for thesemiconductor industry we know today.
Braun's original cold-cathode CRT, the Braun tube, 1897
Braun's enduring fame is largely due to his invention of thecathode-ray tube (CRT), which is still commonly referred to as the "Braun tube"; today, the term typically refers to a high-vacuum tube, in which an electron beam can be deflected in both horizontal and vertical directions. The first version, developed in Strassburg in 1897,[25] was far from perfect; it featured acold cathode and a moderate vacuum, which required a 100,000 Vacceleration voltage to produce a visible trace of the magnetically deflected beam. Furthermore, magnetic deflection affected only one direction, while the other was controlled by a rotating mirror placed in front of thephosphorescent screen.
However, industry immediately recognized the potential of the invention, leading to its further development. By 1899, his assistant,Jonathan Zenneck, introduced oscillations to magnetically control the Y deflection, and later improvements included the addition of a heated cathode, aWehnelt cylinder, and high-vacuum technology. This tube was not only used foroscilloscopes, but also for fullyelectronic television transmission as a picture tube fortelevision sets, although Braun had considered it unsuitable for television.
The CRT became the cornerstone in developing fully electronic television, being a part of every TV, computer, and any other screen setup till the introduction of theLCD screen at the end of the 20th century.[26] It is still occasionally called the "Braun tube" in German-speaking countries (Braunsche Röhre) and other countries such as Korea (브라운관:Buraun-kwan) and Japan (ブラウン管:Buraun-kan).
An earlyresonant transformer invented by Braun used in the coherer radio receivers in wireless telegraphy radio systems made by theTelefunken company in 1903.
Following the invention of his tube, Braun began researching in the field ofwireless telegraphy. A key issue in early radio technology was the development of a reliable receiver. Braun, as a physicist, was accustomed to working under reproducible experimental conditions, which the commonly usedcoherer receivers at the time failed to meet. He replaced the coherer with acrystal detector,[27][28] which greatly improved the sensitivity of the receiver, although the crystal detector required frequent re-adjustment. It was only later that theelectron tube replaced the crystal detector, although devices like germanium diodes continued to be used in simpler receivers for some time. The first FMradar systems still employed a crystal detector.[29]
In late 1898, the technology was commercialized when the chocolate manufacturer from Cologne, Ludwig Stollwerck, founded a consortium to exploit Braun's patents, contributing 560,000 marks in capital. After the successful transmission of signals over longer distances, the consortium was transformed into the "Professor Braun’s Telegraphy Company," which eventually becameTelefunken AG. They set up the first world-wide network of communications,[30] and was the first in the world to sell electronic televisions withcathode-ray tubes in Germany in 1934.[31][32] In 1900, Stollwerck facilitated contact with Professor August Raps, head of theSiemens & Halske Telegraph Construction Company, which later took over the development of the apparatus.
Braun's two circuits to send and receive24 September 1900: Bargman, Braun and telegraphist at wireless station inHeligoland
Braun also made significant contributions to radio transmission technology. WhileGuglielmo Marconi had developed his transmitter primarily through empirical methods, Braun was able to improve it by focusing on the underlying physics. Originally, the resonant and antenna circuits were combined, but he separated them into two parts: a primary circuit consisting of acapacitor and spark gap, and an antenna circuit inductively coupled to it.[33] This innovation allowed for greater energy transmission in the system.
By 1898, the resulting powerful systems made the term "long-distance telegraphy" more appropriate, as the maximum range, previously limited to 20 km, steadily increased. On 24 September 1900, a radio link was successfully established betweenCuxhaven andHelgoland over a distance of 62 km.[34] On 12 December 1901, Marconi received radio signals at his station inPoldhu, Cornwall, at Signal Hill inSt. Johns, Newfoundland, using a transmitter designed in Braun's circuit. Whether this reception actually occurred remains debated in the literature.
Meanwhile, Braun attempted to replace the spark-gap transmitter, which produced damped oscillations, with AC generators that generated undamped oscillations, though he was unable to implement a feedback loop using electron tubes at the time.
A Braun mobile station (1903)
Together withGeorg Graf von Arco andAdolf Slaby, Braun was part of the team that developed the concept for "mobile stations for wireless telegraphy for military purposes," which in 1903 led to a practical implementation byAEG and Siemens & Halske. The system consisted of two horse-drawn wagons: one with all the transmitting and receiving equipment, including a battery, and the other with auxiliary and reserve supplies. This allowed the wagons to be separated in difficult terrain, as the station could still operate with just the front wagon.[35]
Braun also focused on early problems in directional radio—the alignment of transmitting and receiving antennas. He was among the first to achieve directed radiation and optimized antenna performance through calculations.[36][37]
^In Germany he was called the "wireless wizard" and was credited there with having done more than anyone else to perfect control of the new system of communication.
^Ferdinand Braun:Drahtlose Telegraphie durch Wasser und Luft. Veit & Comp., Leipzig 1901. Reprint: Severus-Verlag, Hamburg 2010, ISBN 978-3-942382-02-1.
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)
