Editing Silicon controlled rectifier (section)

{{Short description|Four-layer solid-state current-controlling device}}
{{more citations needed|date=December 2019}}
{{Infobox electronic component
| name              = Silicon controlled rectifier
| image             = 2N3668.jpg
| caption           = [[TO-3]] SCR; 100 [[Volt|V]], 8 [[Ampere|A]]
| type              = Active
| inventor          = Gordon Hall
| first_produced    = 1957
| first_produced_by = [[General Electric]] 
| pins              = [[Anode]], gate, and [[cathode]]
| symbol            = [[File:SCR symbol.svg|150px]]
}}

A '''silicon controlled rectifier''' or '''semiconductor controlled rectifier''' ('''SCR''') is a four-layer [[solid-state electronics|solid-state]] [[Electric current|current]]-controlling device. The name "silicon controlled rectifier" is [[General Electric]]'s trade name for a type of [[thyristor]].  The principle of four-layer p–n–p–n switching was developed by Moll, Tanenbaum, Goldey, and Holonyak of [[Bell labs|Bell Laboratories]] in 1956.<ref>{{Cite journal|last1=Moll|first1=J.|last2=Tanenbaum|first2=M.|last3=Goldey|first3=J.|last4=Holonyak|first4=N.|date=September 1956|title=P-N-P-N Transistor Switches|journal=Proceedings of the IRE|language=en-US|volume=44|issue=9|pages=1174–1182|doi=10.1109/jrproc.1956.275172|s2cid=51673404|issn=0096-8390}}</ref> The practical demonstration of silicon controlled switching and detailed theoretical behavior of a device in agreement with the experimental results was presented by Dr Ian M. Mackintosh of Bell Laboratories in January 1958.<ref>{{Cite book|url=https://books.google.com/books?id=g9Y_DQAAQBAJ|title=Properties and Applications of Transistors|last=Vasseur|first=J. P.|date=2016-06-06|publisher=Elsevier|isbn=9781483138886|language=en}}</ref><ref>{{Cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/4449711.stm|title=Law that has driven digital life|last=Twist|first=Jo|date=2005-04-18|work=BBC News|access-date=2018-07-27|language=en-GB}}</ref> The SCR was developed by a team of [[Power engineering|power engineer]]s led by Gordon Hall
<ref>{{cite web|last=Ward|first=Jack|title=The Early History of the Silicon Controlled Rectifier|url=http://www.semiconductormuseum.com/Transistors/GE/OralHistories/Gutzwiller/Gutzwiller_Page6.htm|access-date=12 April 2014|page=6}}</ref>
<ref>{{cite web |title=Semiconductors: Thyristors and more |url=https://edisontechcenter.org/semiconductors.html |publisher=Edison Tech Center}}</ref>
<ref>{{cite web |title=SCR is 50 Years Old |url=https://ieeemilestones.ethw.org/w/images/5/52/Milestone_Reference_1-SCR_50_Yrs_Old_Owen_IASMag_2007.pdf |publisher=IEEE Industry Applications Magazine}}</ref>
<ref>{{cite news |last1=Mungenast |first1=J. E. |title=The SCR Revolution |url=https://www.rfcafe.com/references/electronics-world/scr-revolution-electronics-world-february-1966.htm |website=RF Cafe |publisher=General Electric Co.}}</ref>
and commercialized by Frank W. "Bill" Gutzwiller in 1957.

Some sources define silicon-controlled [[rectifier]]s and [[thyristor]]s as synonymous<ref>{{Cite book|title=Standard Handbook of Electronic Engineering, 5th Edition|last1=Christiansen|first1=Donald|last2=Alexander|first2=Charles|last3=Jurgen|first3=Ronald|date=2005|publisher=Mcgraw-hill|isbn=9780071384216|language=en}}</ref> while other sources define silicon-controlled rectifiers as a [[Subset#Definitions|proper subset]] of the set of thyristors; the latter being devices with at least four layers of alternating [[N-type semiconductor|n-]] and [[P-type semiconductor|p-type material]].<ref>
[[International Electrotechnical Commission]] 60747-6 standard
</ref><ref>{{Cite book|title=The Electrical Engineering Handbook, Second Edition|last=Dorf|first=Richard C.|date=1997-09-26|publisher=CRC Press|isbn=9781420049763|language=en}}</ref>  According to Bill Gutzwiller, the terms "SCR" and "controlled rectifier" were earlier, and "thyristor" was applied later, as usage of the device spread internationally.<ref>{{cite web|last=Ward|first=Jack|title=The Early History of the Silicon Controlled Rectifier|url=http://www.semiconductormuseum.com/Transistors/GE/OralHistories/Gutzwiller/Gutzwiller_Page7.htm|access-date=12 April 2014|page=7}}</ref>

SCRs are unidirectional devices (i.e. can conduct current only in one direction) as opposed to [[TRIAC]]s, which are bidirectional (i.e. charge carriers can flow through them in either direction). SCRs can be triggered normally only by a positive current going into the gate as opposed to TRIACs, which can be triggered normally by either a positive or a negative current applied to its gate electrode.