Valve amplifier thermionic valves. The simplest valve was invented by John Ambrose Fleming while working for the Marconi Company in London in 1904 and named the diode, as it had two electrodes. The diode conducted electricity in one direction only and was used as a radio detector and a rectifier. In 1906 Lee De Forest added a third electrode and invented the first electronic amplifying device, the triode, which he named the "Audion". This additional "control grid" modulates the current that flows between cathode and anode. The relationship between current flow and plate and grid voltage is often represented as a series
Christopher Rose (electrical engineer) Christopher Rose (electrical engineer) Christopher Rose (born January 9, 1957) is a professor of engineering and associate dean of the faculty at Brown University in Rhode Island and a founding member of WINLAB at Rutgers University in New Jersey. He was educated at the Massachusetts Institute of Technology; SB'79, SM'81, Ph.D'85 all in Course VI (Electrical Engineering and Computer Science). On September 2, 2004, an article by Christopher Rose and Gregory Wright, titled "Inscribed matter as an energy-efficient means of communication with an extraterrestrial civilization", appeared on the cover of "Nature" with the headline "Dear ET...". The article argued that