Editing Diode (section)

== History ==
{{Further|Vacuum tube#History and development}}
[[File:Diode-english-text.svg|thumb|Structure of a [[vacuum tube]] diode. The filament itself may be the cathode, or more commonly (as shown here) used to heat a separate metal tube which serves as the cathode.]]

Thermionic ([[vacuum-tube]]) diodes and [[solid state (electronics)|solid-state]] (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver [[detector (radio)|detectors]].<ref>{{Cite journal|last=Guarnieri|first=M.|date=2011|title=Trailblazers in Solid-State Electronics|journal=IEEE Ind. Electron. M.|volume=5|issue=4|pages=46–47|doi=10.1109/MIE.2011.943016|s2cid=45476055}}</ref> Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable. In addition, most receiving sets had vacuum tubes for amplification that could easily have the thermionic diodes included in the tube (for example the [[12SQ7]] [[double diode triode]]), and vacuum-tube rectifiers and gas-filled rectifiers were capable of handling some high-voltage/high-current rectification tasks better than the semiconductor diodes (such as [[selenium rectifier]]s) that were available at that time.

In 1873, [[Frederick Guthrie (scientist)|Frederick Guthrie]] observed that a grounded, white-hot metal ball brought in close proximity to an electroscope would discharge a positively charged electroscope, but not a negatively charged electroscope.<ref>Guthrie, Frederick (October 1873) [https://books.google.com/books?id=U08wAAAAIAAJ&pg=PA257 "On a relation between heat and static electricity,"] ''The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science'', 4th series, '''46''':  257–266.</ref><ref>[https://www.nobelprize.org/uploads/2018/06/richardson-lecture.pdf 1928 Nobel Lecture:] Owen W. Richardson, "Thermionic phenomena and the laws which govern them", December 12, 1929,</ref> In 1880, Thomas Edison observed unidirectional current between heated and unheated elements in a bulb, later called [[Thermionic emission#History|Edison effect]], and was granted a patent on application of the phenomenon for use in a [[direct current|DC]] [[voltmeter]].<ref>Edison, Thomas A. "Electrical Meter" {{US patent|307030}} Issue date: Oct 21, 1884</ref><ref>{{Cite journal |last=Redhead |first=P. A. |date=1998-05-01 |title=The birth of electronics: Thermionic emission and vacuum |journal=Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films |volume=16 |issue=3 |pages=1394–1401 |doi=10.1116/1.581157 |issn=0734-2101 |bibcode=1998JVSTA..16.1394R}}</ref> About 20 years later, [[John Ambrose Fleming]] (scientific adviser to the [[Marconi Company]] and former Edison employee) realized that the Edison effect could be used as a [[Detector (radio)|radio detector]]. Fleming patented the first true thermionic diode, the [[Fleming valve]], in Britain on 16 November 1904<ref>{{cite web |url=http://www.jmargolin.com/history/trans.htm |title=Road to the Transistor |publisher=Jmargolin.com |access-date=2008-09-22}}</ref> (followed by {{US patent |803684}} in November 1905). Throughout the vacuum tube era, valve diodes were used in almost all electronics such as radios, televisions, sound systems, and instrumentation. They slowly lost market share beginning in the late 1940s due to selenium rectifier technology and then to semiconductor diodes during the 1960s. Today they are still used in a few high power applications where their ability to withstand transient voltages and their robustness gives them an advantage over semiconductor devices, and in musical instrument and audiophile applications.

{{Anchor|Crystal diode}}In 1874, German scientist [[Karl Ferdinand Braun]] discovered the "unilateral conduction" across a contact between a metal and a [[mineral]].<ref>Braun, Ferdinand (1874) [http://gallica.bnf.fr/ark:/12148/bpt6k152378/f580.image.langEN "Ueber die Stromleitung durch Schwefelmetalle"] (On current conduction in metal sulphides), ''Annalen der Physik und Chemie'', '''153''' : 556–563.</ref><ref>[https://web.archive.org/web/20060211010305/http://chem.ch.huji.ac.il/~eugeniik/history/braun.htm Karl Ferdinand Braun]. chem.ch.huji.ac.il</ref> Indian scientist [[Jagadish Chandra Bose]] was the first to use a crystal for detecting radio waves in 1894.<ref name="Sarkar">{{Cite book |last = Sarkar |first= Tapan K. |title = History of wireless  |publisher = John Wiley and Sons |year = 2006 |location = US |pages = 94, 291–308 |url = https://books.google.com/books?id=NBLEAA6QKYkC&pg=PA291 |isbn = 0-471-71814-9}}</ref> The [[crystal detector]] was developed into a practical device for [[wireless telegraphy]] by [[Greenleaf Whittier Pickard]], who invented a [[silicon]] crystal detector in 1903 and received a patent for it on 20 November 1906.<ref>Pickard, G. W., "Means for receiving intelligence communicated by electric waves" {{US patent|836531}} Issued: August 30, 1906</ref> Other experimenters tried a variety of other minerals as detectors. Semiconductor principles were unknown to the developers of these early rectifiers. During the 1930s understanding of physics advanced and in the mid-1930s researchers at Bell Telephone Laboratories recognized the potential of the crystal detector for application in microwave technology.<ref name="Scaff_Ohl_01">Scaff, J. H., Ohl, R. S. [https://archive.org/details/bstj26-1-1 "Development of Silicon Crystal Rectifiers for Microwave Radar Receivers"], ''The Bell System Technical Journal'', Vol. 24, No. 1, January 1947. pp. 1 - 30</ref> Researchers at [[Bell Labs]], [[Western Electric]], [[MIT]], [[Purdue]] and in the [[UK]] intensively developed point-contact diodes (''crystal rectifiers'' or ''crystal diodes'') during World War II for application in radar.<ref name="Scaff_Ohl_01"/> After World War II, AT&T used these in its microwave towers that criss-crossed the United States, and many radar sets use them even in the 21st century. In 1946, Sylvania began offering the 1N34 crystal diode.<ref>Cornelius, E. C. [http://www.americanradiohistory.com/Archive-Electronics/40s/Electronics-1946-02.pdf "Germanium Crystal Diodes"], ''Electronics'', February 1946, p. 118</ref><ref>{{cite web |url = http://www.bunkerofdoom.com/tubes/syl43/DATA/1949/1N34.GIF |title = Sylvania 1949 data book page |archive-url=https://web.archive.org/web/20180525062316/http://www.bunkerofdoom.com/tubes/syl43/DATA/1949/1N34.GIF |archive-date=25 May 2018 |url-status=dead}}</ref><ref>Sylvania, [http://n4trb.com/AmateurRadio/SemiconductorHistory/40%20Uses%20for%20Germanium%20Diodes.pdf ''40 Uses for Germanium Diodes''], Sylvania Electric Products Co., 1949, p. 9</ref> During the early 1950s, junction diodes were developed.