Editing Karl Ferdinand Braun (section)

===Radio Receiver===
[[File:Braun wireless receiving transformer 1905.jpg|thumb|An early resonant transformer invented by Braun used in the coherer radio receivers in wireless telegraphy radio systems made by the Telefunken company in 1903.]]

Following the invention of his tube, Braun also began researching in the field of wireless 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 used coherer receivers at the time failed to meet. He replaced the coherer with a [[crystal detector]],<ref name="Seitz" /><ref>{{Citation |last=Braun |first=F. |author-link=Ferdinand Braun |year=1874 |url=https://books.google.com/books?id=YBJbAAAAYAAJ&pg=PA556 |title=Ueber die Stromleitung durch Schwefelmetalle |trans-title=On current conduction through metal sulfides |language=de |journal=Annalen der Physik und Chemie |volume=153 |issue=4 |pages=556–563 |doi=10.1002/andp.18752291207|bibcode=1875AnP...229..556B }}</ref> which greatly improved the sensitivity of the receiver, although the crystal detector required frequent re-adjustment. It was only later that the electron tube replaced the crystal detector, although devices like germanium diodes continued to be used in simpler receivers for some time. The first FM radar systems still employed a crystal detector.<ref>{{cite web | url=https://mwsherman.com/fmonly/fm_only_lowtech.html | title=FM only: Low Tech FM Radios }}</ref>

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 became [[Telefunken|Telefunken AG]], set up the first world-wide network of communications<ref name="historyisnowmagazine.com">{{Cite web |date=2014-03-02 |title=The Scientist who World War I wrote out of history |url=http://www.historyisnowmagazine.com/blog/2014/3/2/the-scientist-who-world-war-i-wrote-out-of-history |access-date=2023-09-27 |website=History is Now Magazine, Podcasts, Blog and Books {{!}} Modern International and American history |language=en-US}}</ref> and was the first in the world to sell electronic televisions with [[cathode-ray tube]]s, in Germany in 1934.<ref name="etf"/><ref>[http://www.tvhistory.tv/1934-35-Telefunken-FEIII.JPG 1934–35 Telefunken], Television History: The First 75 Years.</ref> In 1900, Stollwerck facilitated contact with Professor August Raps, head of the Siemens & Halske Telegraph Construction Company, which later took over the development of the apparatus.

See more: [[Crystal detector]]