- German physicist
who made improvements to Guglielmo Marconi's system of wireless telegraphy;
they shared the 1909 Nobel Prize for Physics. Braun also discovered
crystal rectifiers (used in early radios), and invented the oscilloscope
1895.
Braun was born in Fulda, Hesse, and educated at Marburg and Berlin.
He held academic posts at a number of German universities, ending
his career as professor and from 1895 director of the Institute of
Physics at Strasbourg.
In an attempt to increase the radio transmitter range to more than
15 km/9 mi, Braun devised a system in which the power from the transmitter
was magnetically coupled (using electromagnetic induction) to the
antenna circuit. He patented this invention 1899, and the principle
of magnetic coupling has since been applied to all similar transmission
systems. Later Braun developed directional antennas.
In 1874 Braun discovered that some mineral metal sulphides conduct
electricity in one direction only. These were later used in the crystal
radio receivers that preceded valve circuits.
Braun's oscilloscope was an adaptation of the cathode-ray tube. A
laboratory instrument to study high-frequency alternating currents,
it was the forerunner of television and radar display tubes.
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