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The first radio receivers invented by Marconi, Oliver Lodge and Alexander Popov in 1894–5 used a primitive radio wave detector called a coherer, invented in 1890 by Edouard Branly and improved by Lodge and Marconi. [1] [6] [9] [12] [16] [17] [18] The coherer was a glass tube with metal electrodes at each end, with loose metal powder between ...
Valdemar Poulsen (23 November 1869 – 23 July 1942) was a Danish engineer who developed a magnetic wire recorder called the telegraphone in 1898. He also made significant contributions to early radio technology, including the first continuous wave radio transmitter, the Poulsen arc, [1] which was used for a majority of the earliest audio radio transmissions, before being supplanted by the ...
In Popov's lightning detector the coherer (C) was connected to an antenna (A), and to a separate circuit with a relay (R) and battery (V) which operated an electric bell (B). The radio noise generated by a lightning strike turned on the coherer, the current from the battery was applied to the relay, closing its contacts, which applied current ...
The most common type of receiver before vacuum tubes was the crystal set, although some early radios used some type of amplification through electric current or battery. Inventions of the triode amplifier, motor-generator, and detector enabled audio radio.
Before the discovery of electromagnetic waves and the development of radio communication, there were many wireless telegraph systems proposed and tested. [4] In April 1872 William Henry Ward received U.S. patent 126,356 for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire. [5]
(Before that, the most common type of receiver was the crystal set, although some early radios used some type of amplification through electric current or battery.) Inventions of the triode amplifier, generator, and detector enabled audio radio. Westinghouse buys DeForest's and Armstrong's patent.
Collins became an expert in radio technology, writing many books on the subject, and conducting research on improving radio components. An unusual example were his experiments in using brain tissue to detect radio waves. [6] [7] [8] The first radio receivers prior to 1904 used a primitive device called a coherer to detect the radio waves. The ...
"Olympia suitcase", battery-powered portable radio receiver, introduced. The first mobile television camera (180 lines, all-electronic) is used for live television broadcasts of the Olympic Games. Also in the UK are first regular television broadcasts – now for the perfect electronic EMI system, which soon replaced the mechanical part Baird ...