Editing Triode (section)

===Invention===
Triodes came about in 1906 when American engineer [[Lee de Forest]]<ref name="Tyne6">{{cite journal
  | last1  = Tyne
  | first1 = Gerald F. J.
  | title = The Saga of the Vacuum Tube, Part 6
  | journal = Radio News
  | volume = 30
  | issue = 3
  | pages = 26–28, 91
  | publisher = Ziff-Davis
  | location = Chicago, IL
  | date = September 1943
  | url = http://www.americanradiohistory.com/Archive-Radio-News/40s/Radio-News-1943-09.pdf
  | access-date = November 30, 2016}}</ref> and Austrian physicist [[Robert von Lieben]]<ref name="Tyne8">{{cite journal
  | last1  = Tyne
  | first1 = Gerald F. J.
  | title = The Saga of the Vacuum Tube, Part 8
  | journal = Radio News
  | volume = 30
  | issue = 5
  | pages = 26–28
  | publisher = Ziff-Davis
  | location = Chicago, IL
  | date = November 1943
  | url = http://www.americanradiohistory.com/Archive-Radio-News/40s/Radio-News-1943-11-R.pdf
  | access-date = November 30, 2016}}</ref> independently patented tubes that added a third  electrode, a [[control grid]], between the filament and plate to control current.<ref name="Anton A. Huurdeman 2003, page 226">Anton A. Huurdeman, The Worldwide History of Telecommunications, John Wiley & Sons - 2003, page 226</ref><ref>John Bray, The Communications Miracle: The Telecommunication Pioneers from Morse to the Information Superhighway, Springe - 2013, pages 64-65</ref> Von Lieben's partially-evacuated three-element tube, patented in March 1906, contained a trace of [[mercury (element)|mercury vapor]] and was intended to amplify weak telephone signals.<ref>[http://www.hts-homepage.de/Lieben/Lieben.html] DRP 179807</ref><ref>[[Tapan K. Sarkar]] (ed.) "History of wireless", John Wiley and Sons, 2006. {{ISBN|0-471-71814-9}}, p.335</ref><ref>Sōgo Okamura (ed), ''History of Electron Tubes'', IOS Press, 1994 {{ISBN|90-5199-145-2}} page 20</ref><ref name="Tyne8" /> Starting in October 1906<ref name="Anton A. Huurdeman 2003, page 226"/> De Forest patented a number of three-element tube designs by adding an electrode to the diode, which he called [[Audion]]s, intended to be used as radio detectors.<ref name="De Forest">{{cite journal
  | last = De Forest
  | first = Lee
  | title = The Audion; A New Receiver for Wireless Telegraphy
  | journal = Trans. AIEE
  | volume = 25
  | pages = 735–763
  | publisher = American Institute of Electrical and Electronics Engineers
  | date = January 1906
  | url = https://babel.hathitrust.org/cgi/pt?id=uiug.30112089533605&view=1up&seq=356
  | doi = 10.1109/t-aiee.1906.4764762
  | access-date = March 30, 2021}} The link is to a reprint of the paper in the ''Scientific American Supplement'', Nos. 1665 and 1666, November 30, 1907 and December 7, 1907, p.348-350 and 354-356</ref><ref name="Tyne6" /> The one which became the design of the triode, in which the grid was located between the filament and plate, was patented January 29, 1907.<ref name="AudionPatent" >{{US patent|879532}}, ''[https://patents.google.com/patent/US879532 Space Telegraphy]'', filed January 29, 1907, issued February 18, 1908</ref><ref name="Tyne6" /><ref name="Hijiya">{{cite book
 | last1  = Hijiya
 | first1 =  James A. 
 | title  = Lee de Forest and the Fatherhood of Radio
 | publisher = Lehigh University Press
 | date   = 1997
 | pages  = 77
 | url    = https://books.google.com/books?id=JYylHhmoNZ4C&q=%22+audion+%22+1907&pg=PA77
 | isbn   = 0934223238
 }}</ref> Like the von Lieben vacuum tube, De Forest's Audions were incompletely evacuated and contained some gas at low pressure.<ref name="Okamura">{{cite book
  | last = Okamura
  | first = Sōgo 
  | title = History of Electron Tubes
  | publisher = IOS Press
  | year = 1994
  | pages = 17–22
  | url = https://books.google.com/books?id=VHFyngmO95YC&q=Audion+triode&pg=PA21
  | isbn = 9051991452}}</ref><ref name="Lee">{{cite book
  | last = Lee
  | first = Thomas H. 
  | title = Planar Microwave Engineering: A Practical Guide to Theory, Measurement, and Circuits
  | publisher = Cambridge University Press
  | year = 2004
  | pages = 13–14
  | url = https://books.google.com/books?id=uoj3IWFxbVYC&q=Audion+triode&pg=PA13
  | isbn = 0521835267}}</ref> von Lieben's vacuum tube did not see much development due to his death seven years after its invention, shortly before the outbreak of the [[First World War]].<ref>John Bray, The Communications Miracle: The Telecommunication Pioneers from Morse to the Information Superhighway, Springe - 2013, page 64</ref>

De Forest's Audion did not see much use until its ability to amplify was recognized around 1912 by several researchers,<ref name="Lee" /><ref name="Nebeker">{{cite book
  | last = Nebeker
  | first = Frederik
  | title = Dawn of the Electronic Age: Electrical Technologies in the Shaping of the Modern World, 1914 to 1945
  | publisher = John Wiley & Sons
  | year = 2009
  | pages = 14–15
  | url = https://books.google.com/books?id=xwmH6-q5O5AC&q=nebeker+audion+%22De+forest&pg=PA14
  | isbn = 978-0470409749}}</ref> who used it to build the first successful amplifying radio receivers and [[electronic oscillator]]s.<ref name="Hempstead">{{cite book
  | last = Hempstead
  | first = Colin
  |author2=William E. Worthington
   | title = Encyclopedia of 20th-Century Technology, Vol. 2
  | publisher = Taylor & Francis
  | year = 2005
  | pages = 643
  | url = https://books.google.com/books?id=0wkIlnNjDWcC&q=%22H+J+triode%22+audion&pg=PA648
  | isbn = 1579584640}}</ref><ref name="Armstrong1915">{{cite journal
|last=Armstrong
|first=E.H.
|author-link=Edwin Howard Armstrong
|pages=215–247
|title=Some Recent Developments in the Audion Receiver 
|journal=Proceedings of the IRE 
|volume=3 
|number=9 
|date=September 1915
|doi=10.1109/jrproc.1915.216677|s2cid=2116636
|url=https://zenodo.org/record/1432482
}}. Republished as {{cite journal 
|last=Armstrong 
|first=E.H. 
|author-link=Edwin Howard Armstrong 
|title=Some Recent Developments in the Audion Receiver 
|journal=Proceedings of the IEEE 
|volume=85 
|number=4 
|date=April 1997
|url=http://www.ieee.org/documents/00573757.pdf 
|pages=685–697
|doi=10.1109/jproc.1997.573757}}</ref> The many uses for amplification motivated its rapid development. By 1913 improved versions with higher vacuum were developed by Harold Arnold at [[American Telephone and Telegraph Company]], which had purchased the rights to the Audion from De Forest, and [[Irving Langmuir]] at [[General Electric]], who named his tube the "Pliotron",<ref name="Lee" /><ref name="Nebeker" /> These were the first [[vacuum tube]] triodes.<ref name="Okamura" /> The name "triode" appeared later, when it became necessary to distinguish it from other kinds of vacuum tubes with more or fewer elements ([[Diode#Vacuum tube diodes|diode]]s, [[tetrode]]s, [[pentode]]s, etc.). There were lengthy lawsuits between De Forest and von Lieben, and De Forest and the [[Marconi Company]], who represented [[John Ambrose Fleming]], the inventor of the diode.<ref name=Hijiya92 >James A. Hijiya, ''Lee de Forest and the Fatherhood of Radio Political, and Economic Development '' Lehigh University Press, 1992. {{ISBN|0934223238}}, pages 93-94</ref>