Édouard Branly
(23 October 1844 – 24 March 1940)
Édouard Eugène Désiré Branly was born in Amiens, France, and died in Paris, France. He was a French inventor, physicist and professor at the "Institut Catholique de 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 it upon the discoveries of Temistocle Calzecchi-Onesti, who demonstrated in experiments made between 1884 and 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, until about 1907 when British radio pioneer Oliver Lodge made the coherer into a practical receiver by adding a "decoherer" which tapped the coherer after each reception to dislodge clumped filings, thus restoring the device's sensitivity.
Without the work of Branly, Guglielmo Marconi would have been able to make 1895 the telegraph connections that made him famous.
Branly was three times nominated for a Nobel Prize, but he never received it.
