Karl Ferdinand Braun, who in 1909 shared the Nobel Prize for Physics with Marconi, was born in Tulda, Germany in 1850. He taught at the universities of Würzburg, Marburg and Strassburg, the latter becoming his principal seat of activity. Around 1895 he carried out important research on the cathode ray, much of it using the tube he had invented (the so-called "Braun tube"), a prototype which would later develop into the modern-day cathode-ray tube. Braun left many writings on the electromagnetic theory of light.

From 1898, after researching hydrotelegraphy, he devoted himself to wireless telegraphy and invented a system similar to Marconi's, but with some improvements. This equipment, called the Braun-Siemens system, began to compete with the A.E.G.-Slaby-Arco system in the race to develop an independent German wireless telegraphy system which was promoted by Emperor Wilhelm II. The race was concluded on 27 May 1903 by the union of the two systems and a new company was formed in order to protect the national interest from the overpowering success of the Marconi system.

Like Adolf Slaby, Braun concentrated mainly on the development of ever more efficient and competitive devices although his contribution to the field of wireless telegraphy was not as important as that for the cathode-ray tube technology.

When in 1909 at Stockholm, Braun was awarded the Nobel Prize together with Marconi, he was fifty-nine, more than two decades older than his Italian colleague. Although he had an outstanding background, many other scientists deserved the prize too and it is highly probable that his nomination at Marconi's side was political.

Marconi at first refused to receive "half a prize", but finally decided to accept and went to Stockholm. However, when he gave his speech at the Swedish Royal Academy, he only cited Braun once, when he explained that part of his work on condensers in association with radiating antennae had been carried out simultaneously by Braun, without either of them knowing anything of the other's work.

Some years later, Braun went to the United States to testify in court on the property of a patent and in 1918 he died in New York. He had not undertaken any new research for at least ten years.