electromagnetic relay
81Copper wire and cable — Copper has been used in electric wiring since the invention of the electromagnet and the telegraph in the 1820s.[1][2] The invention of the telephone in 1876 proved to be another early boon for copper wire.[3] Today, despite competition from… …
82Multipath propagation — This article is about the electromagnetic propagation phenomenon. For the computing storage term, see Multipath I/O. For the routing term, see Multipath Routing. In wireless telecommunications, multipath is the propagation phenomenon that results …
83Bell Labs — Bell Laboratories (also known as Bell Labs and formerly known as AT T Bell Laboratories and Bell Telephone Laboratories) is the research organization of Alcatel Lucent and previously the American Telephone Telegraph Company (AT T). Bell… …
84Switch — For other uses, see Switch (disambiguation). Electrical switches. Top, left to right: circuit breaker, mercury switch, wafer switch, DIP switch, surface mount switch, reed switch. Bottom, left to right: wall switch (U.S. style), miniature toggle… …
85Coherer — Metal filings coherer The coherer was a primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the twentieth century. Invented around 1890 by French scientist Édouard… …
86Bifilar coil — A bifilar coil is an electromagnetic coil that contains two closely spaced, parallel windings. In engineering, the word bifilar describes wire which is made of two filaments or strands. It is commonly used to denote special types of winding wire… …
87military communication — Introduction the transmission of information from reconnaissance and other units in contact with the enemy and the means for exercising command by the transmission of orders and instructions of commanders to their subordinates. As such, it… …
88Near field communication — An NFC enabled mobile phone interacting with a SmartPoster Near field communication, or NFC, allows for simplified transactions, data exchange, and wireless connections between two devices in proximity to each other, usually by no more than a few …
89Ultra high frequency — (UHF) designates a range (band) of electromagnetic waves with frequencies between 300 MHz and 3 GHz (3,000 MHz). Also known as the decimeter band or decimeter wave as the wavelengths range from ten to one decimeters. Radio waves with frequencies… …
90Signal Corps (United States Army) — U.S. Army Signal Corps Coat of Arms Active 3 March 1863 – Present Country …
