Braun, Karl Ferdinand (1850-1918), a German physicist, made important contributions to the early technology of radio. The first television screens were descended from one of Braun’s inventions. He shared the 1909 Nobel Prize in physics with the Italian radio pioneer Guglielmo Marconi.
Braun studied electricity and invented several electrical instruments. The most important of these was a type of vacuum tube called the cathode-ray oscilloscope, which he devised in 1897 (see Oscilloscope). Braun formed the rays in the cathode-ray tube into a fine beam that could trace out patterns on the phosphorescent face of the tube. At first, this was important as a scientific instrument for displaying and measuring oscillating voltages. Later it became the forerunner of the television picture tube and the radar screen.
In 1898, Braun began to experiment with radio, then called wireless telegraphy. He improved the design of the transmitting aerial so that signals could be broadcast much farther than the 9 miles (15 kilometers) or so that had been the previous limit. He also found ways of directing radio waves into a beam, like a searchlight beam, which further increased their range. It was for this work that he shared the 1909 Nobel Prize with Marconi.
Braun was born on June 6, 1850, in the German city of Fulda. He gained his doctorate from the University of Berlin in 1872. He held appointments in many German universities, becoming principal of the Institute of Physics in Strasbourg (now France) in 1895. Braun was visiting New York City as a witness in a patent dispute when the United States entered World War I (1914-1918). He was detained as a citizen of an enemy country and was still in the United States when he died on April 20, 1918.
