{{Short description|Pentode vacuum tube}} {{Infobox vacuum tube |classification = Pentode <!-- Mandatory --> |service = Digital computers
|height_in = 3+5/32 <!-- inches --> |diameter_in = 1 +3/16 <!-- inches --> |weight_lbs = <!-- pounds -->
<!-- Cathode --> |cathode_type = Coated Unipotential <!-- Mandatory --> |heater_voltage = 7.0 V (6.3 V nominal) |heater_current = 800 mA
<!-- Anode --> <!-- use either max_dissipation or max_current --> |max_dissipation = 8.5 W |max_voltage = 200 V
<!-- Socket Connections --> |pinout = thumb|8V-L-O Pin 1 – Heater <br /> Pin 2 – Anode (Plate) <br /> Pin 3 – Grid 2 (Screen) <br /> Pin 4 – Grid 3 (Suppressor) <br /> Pin 5 – n.c. <br /> Pin 6 – Grid 1 (Control) <br /> Pin 7 – Cathode <br /> Pin 8 – Heater
|reference = https://web.archive.org/web/20221114011216/http://www.nj7p.org/Tubes/PDFs/Frank/137-Sylvania/7AK7.pdf }}
The '''7AK7''' is a pentode vacuum tube (thermionic valve). According to its manufacturer, Sylvania, it was "designed for service in electronic computers".<ref>Sylvania. [https://web.archive.org/web/20221114011216/http://www.nj7p.org/Tubes/PDFs/Frank/137-Sylvania/7AK7.pdf Engineering Data Service. 7AK7]. July 1953.</ref>
thumb|7AK7 vacuum tubes in a 1956 UNIVAC I computer
The tube was developed in 1948,<ref name="Green2010">{{cite book|first1=Tom|last1=Green|title=Bright Boys: The Making of Information Technology|publisher=CRC Press|year=2010|page=[https://archive.org/details/Bright_Boys_The_Making_of_Information_Technology_by_Tom_Green_2010/page/n150 141]|isbn=978-1568814766|url=https://archive.org/details/Bright_Boys_The_Making_of_Information_Technology_by_Tom_Green_2010}}</ref> designed at the request of L. D. Wilson for use in the Whirlwind computer.<ref>{{cite conference |first=L. D.|last=Wilson|title=Tube Reliability in the Univac|book-title=Proceedings of the National Electronics Conference|volume=10|publisher=National Engineering Conference, Incorporated|year=1954|article=746|pages=699–703}}</ref> Significant attention was directed towards its manufacturing process in order to ensure the part's reliability.<ref> David R. Brown, T. F. Clough, and P. Youtz. Investigation of 7AK7 Processing, Emporium, Pa., March 2, 1948. URI: http://hdl.handle.net/1721.3/38986</ref> Dubbed the "computer tube",<ref>{{cite book |last1=Haigh |first1=Thomas |first2=Mark |last2=Priestley |first3=Crispin |last3=Ropefir |title=ENIAC in Action: Making and Remaking the Modern Computer |year= 2016 |publisher=MIT Press |isbn=9780262334419 | page=211}}</ref> it became a popular tube for computers for a while.<ref name="Green2010" /> IBM, however, switched to more compact miniature tubes, starting with the IBM 604 in 1948.
==See also== * 5965, a triode developed for early digital computers * 25L6, a tetrode found in early computers
==References== {{reflist}} {{comp-hardware-stub}} Category:Computer vacuum tubes