Search results
Results From The WOW.Com Content Network
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]
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 poor performance of the coherer led to much research to find a better radio wave detector.
The crystal detector was the most successful of many detector devices invented during this era. The crystal detector evolved from an earlier device, [40] the first primitive radio wave detector, called a coherer, developed in 1890 by Édouard Branly and used in the first radio receivers in 1894–96 by Marconi and Oliver Lodge.
Greenleaf Whittier Pickard (February 14, 1877 – January 8, 1956) was an American electrical engineer and inventor.. While not the earliest discoverer of the rectifying properties of contact between certain solid materials, he was largely responsible and most famous for the development of the crystal detector, the earliest type of diode detector. [1]
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. [22] [27] [29] [32] [36] [37] [38] The coherer was a glass tube with metal electrodes at each end, with loose metal powder between ...
Trevor Graham Baylis CBE (13 May 1937 – 5 March 2018) was an English inventor best known for the wind-up radio.The radio, instead of relying on batteries or external electrical source, is powered by the user winding a crank.