A coherer (or, sometimes, receiver) is an early form of detector in wireless telegraphy. It is a basic electromagnetic wave detector for various wavelengths. It has a circuit that obtains signals from modulated radio waves. The coherer decodes the signals.

The invention of the device is credited to David Edward Hughes, among others. Oliver Joseph Lodge, in his Royal Institute lectures ("The Work of Hertz and Some of His Successors") coined the term "coherer" and gained the "syntonic" (or tuning) patent from the United States Patent Office. In 1892, Edouard Branley invented a coherer (which was named after him). Also, Alexander Popov developed a device similar to the "Branley coherer" to detect atmospheric radiant energy.

Nikola Tesla developed specialized coherers. Tesla noted, in 1893, such devices and explained the connections and the arrangement of transceiving used later by Guglielmo Marconi.

See also

• Radio receiver (electronic device that receives a radio signal from a transmitter)
• List of electronics topics

External links

• "The Coherer (http://home.luna.nl/~arjan-muil/radio/coherer.html)". World of Wireless, Virtual radiomuseum.
• "Coherer / Receiver (http://www.marconicalling.com/museum/html/objects/apparatus/objects-i=3.001-t=3-n=0.html)". Marconi Calling Company.
• Slaby, Adolphus, "The New Telegraphy (http://earlyradiohistory.us/1898sla.htm), Recent experiments in telegraphy with sparks.". The Century Magazine. April, 1898. (Earlyradiohistory.us)

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