Ferdinand Braun

See also: Braun

Karl Ferdinand Braun (1850 - 1918) was born in 1850 with Fulda in the center from the Germany. It supported a thesis under the direction of Hermann Ludwig von Helmholtz in 1872 in Berlin. It comes first once to Strasbourg, for two years in 1880 as invited professor (extraordinarius); it returns definitively, in 1895, as professor (ordinarius) directing of the Institute of Physics. It goes to New York in 1915 to testify in a lawsuit in recognition to patent in radioelectricity. It is stopped and retained for its German nationality by the American authorities and dies before the end of the war, in 1918.

Work

Especially interested physicist by fundamental physics, several of its work were at the origin of interesting applications.

As of the 25 years age, in 1874, it establishes that the Galène (lead sulfide) does not respect the Loi of Ohm: under certain conditions it does not conduct the electricity in the same way according to whether one applies a tension in a direction or another.

Professor at the university of Strasbourg (it had Jonathan Zenneck as raises), it was interested in the fast electric phenomena and to be able to study them it developed in 1897 a particular Cathode tube, known as tube of Braun. Its invention led quickly to the development of the Oscilloscope, which later, was going to make it possible to build the cathode tubes of the Téléviseur S, then first screens of Ordinateur S. Braun used its invention in the company “Professor Braun Telegrafen GMBH” which will become later “Telefunken AG”.

It launches out in 1898 in the boiling in progress on the Transmission without wire (TSF). At that time, the radio operator devices of Guglielmo Marconi have a limited range to 15 km, insufficient for practical applications. In these radios, without amplifier, the antenna is an integral part of the circuit of agreement. Using its knowledge in physics, Braun separates the antenna from the circuit of agreement by using between them an inductive coupling. It removes the spark of the circuits thus limiting the losses of energy and increasing the sensitivity. It brevette, in 1899, its system, which enables him to cover in Cuxhaven a distance of 62 km.

In 1906, it used its knowledge of the properties of conduction of crystal to imagine a rectifier, which one can regard as the ancestor of the modern diode, which allowed the rise of the Poste crystal.

The Nobel Prize of physique was allotted to him in 1909, with Guglielmo Marconi, for its work on the wireless telegraphy.

Bonds and references

“ Ferdinand Braun, route of a Cathodic Nobel. François Mauviard and Georges Frick.

” Site of the association of the museums of sciences of Strasbourg (AMUSS).

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