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Eugène Édouard Désiré Branly (23 October 1844 – 24 March 1940) was a French inventor and physicist. He was the Physics professor at the Catholic University of Paris. He is primarily known for his early involvement in wireless telegraphy and his invention of the Branly coherer around 1890.

The coherer was the first widely used detector for radio communication. Branly built upon the discoveries of Temistocle Calzecchi-Onesti, who demonstrated in experiments in 1884 through 1886 that iron filings contained in an insulating tube will conduct an electrical current under the action of an electromagnetic wave. The operation of the coherer is based upon the large resistance offered to the passage of electric current by loose metal filings, which decreases under the influence of radio frequency alternating current. The coherer became the basis for radio reception, and remained in widespread use for about ten years. This was used by, amongst others, Guglielmo Marconi, in his early experiments. Oliver Joseph Lodge improved Edouard Branly's coherer radio wave detector by adding a "trembler" which periodically dislodged clumped filings, thus restoring the device's sensitivity. The next innovation in electronic detection, between Nikola Tesla's and Guglielmo Marconi's progress in radio in the 1890s and the 1948 invention of the transistor, was Lee De Forest's Audion tube (1906) which replaced Branly device in many instances.

In 1911 he was elected to the French Academy of Sciences

Edouard Branly died in 1940 and was interred in the Père Lachaise cemetery in Paris.

• Radio: History of radio, Invention of radio
• People: Alexander Stepanovich Popov, Karl Ferdinand Braun
• Other: List of people on stamps of France

• Eugenii Katz, "Edouard Eugène Désiré Branly". The history of electrochemistry, electricity and electronics; Biosensors & Bioelectronics.
• "Edouard Branly". Robert Appleton Company, The Catholic Encyclopedia, Volume II, 1907.
• "Edouard Eugène Désiré Branly"". Adventures in Cybersound.