Editing ZX81 (section)

{{Short description|Inexpensive home computer by Sinclair Research, 1981}}
{{Good article}}
{{Use British English|date=March 2023}}
{{Use dmy dates|date=July 2023}}
{{Infobox information appliance
 | name          = Sinclair ZX81
 | image         = Sinclair-ZX81.png
 | caption       =
 | developer     = [[Sinclair Research]]
 | manufacturer  = [[Timex Corporation]]
 | type          = [[Home computer]]
 | generation    =
 | releasedate   = {{Start date and age|df=yes|1981|03|05}}<ref name="FT 6 Mar 1981">[[#FT060381|Crisp (6 March 1981)]]</ref>
 | lifespan      =
 | price         = £49.95 kit, £69.95 assembled<ref name="SRadvert" /> (£{{Inflation|UK|49.95|1981|r=0}}–{{Inflation|UK|69.95|1981|r=0}}/${{To USD|{{Inflation|UK|49.95|1981}}|GBR|round=yes}}–{{To USD|{{Inflation|UK|69.95|1981}}|GBR|round=yes}} at {{CURRENTYEAR}} prices)
 | discontinued  = 1984
 | unitssold     = More than 1.5&nbsp;million<ref name="Sinclair-Research">{{cite web| title = Sinclair ZX81
   | publisher = Sinclair Research
   | url = http://www.sinclairzx.com/about-us.html#12 | url-status = dead
   | archive-url = https://web.archive.org/web/20141214131822/http://www.sinclairzx.com/about-us.html#12
   | access-date = 5 January 2011 | archive-date = 14 December 2014
 }}</ref>
 | unitsshipped  =
 | media         =
 | os            = [[Sinclair BASIC]]<ref name="ZX81OS" />
 | power         = 9V DC<ref name="ZX81OS" />
 | cpu           = [[Z80]] @ 3.25&nbsp;MHz<ref name="ZX81OS" />
 | storage       = External [[Compact Cassette (data)|Compact Cassette]] recorder at a claimed 250 bit/s<ref name="ZX81OS" /> or an average 300 bit/s<ref name="MyPrius" />
 | memory        = 1&nbsp;[[kilobyte|KB]] (64&nbsp;KB max. 56&nbsp;KB usable)<ref name="ZX81OS" />
 | display       = [[Binary image|Monochrome]] display on UHF television<ref name="ZX81OS" />
 | graphics      = 24 lines × 32 characters or<br /> 64 × 48 pixels graphics mode<ref name="ZX81OS" />
 | sound         =
 | input         =
 | controllers   =
 | camera        =
 | touchpad      =
 | connectivity  =
 | service       = <!-- online service/s offered -->
 | dimensions    = {{convert|167|mm|in}} wide by {{convert|175|mm|in}} deep<ref name=ZXComp198210>{{cite journal | title = Machine Specifications
   | journal = ZX Computing | via = [[Internet Archive]]
   | date = October 1982 | issue = 3
   | url = https://archive.org/details/ZXComputingJunJul1985/ZXComputing/ZXComputing_Oct-Nov_1982/page/n129
   }}</ref>
 | weight        = {{convert|350|g|oz}}<ref name="ZX81OS" />
 | topgame       =
 | compatibility =
 | predecessor   = [[ZX80]]
 | successor     = [[ZX Spectrum]]
 | related       = [[Timex Sinclair 1000]],<br />[[Timex Sinclair 1500]]
 | website       =
}}

The '''ZX81''' is a [[home computer]] that was produced by [[Sinclair Research]] and manufactured in [[Dundee]], Scotland, by [[Timex Corporation]]. It was launched in the [[United Kingdom]] in March 1981 as the successor to Sinclair's [[ZX80]] and designed to be a low-cost introduction to home computing for the general public. It was hugely successful; more than 1.5&nbsp;million units were sold.<ref name=danton>{{cite book|first=Tim|last=Danton|quote="“the membrane keyboard was about as joyful to type on as tapioca pudding, and it had some idiosyncrasies that only a mother could love”" |year=2021|title=The Computers That Made Britain — The Home Computer Revolution of the 1980s|isbn=9781912047857|oclc=1428903627|pages=295 |url=https://archive.org/details/computers-that-made-britain|publisher=Raspberry Pi Press|location=Cambridge}}</ref> In the United States it was initially sold as the '''ZX-81''' under licence by Timex. Timex later produced its own versions of the ZX81: the [[Timex Sinclair 1000]] and [[Timex Sinclair 1500]]. Unauthorized [[List of ZX80 and ZX81 clones|ZX81 clones]] were produced in several countries.

The ZX81 was designed to be small, simple, and above all, inexpensive, with as few components as possible. Video output was designed for a television set rather than a dedicated [[computer monitor|monitor]]. [[computer program|Programs]] and data are [[Loader (computing)|loaded]] and saved onto [[compact audio cassette]]s. It uses only four [[silicon chips]] and 1&nbsp;KB of [[computer memory|memory]]. It has no power switch or moving parts, with the exception of a [[Very high frequency|VHF]] TV channel selector switch present in some models. It has a pressure-sensitive [[membrane keyboard]]. The ZX81's limitations prompted a market in third-party peripherals to improve its capabilities. Its distinctive case and keyboard brought designer [[Rick Dickinson]] a [[Design Council]] award.

The ZX81 could be bought by mail order preassembled or, for a lower price, in kit form. It was the first inexpensive mass-market home computer to be sold by [[high street]] stores, led by [[W. H. Smith]] and soon many other retailers. The ZX81 marked the point when computing in Britain became an activity for the general public rather than the preserve of businessmen and electronics hobbyists. It produced a huge community of enthusiasts, some of whom founded their own businesses producing software and hardware for the ZX81. Many went on to have roles in the British computer industry. The ZX81's commercial success made Sinclair Research one of Britain's leading computer manufacturers and earned a fortune and an eventual knighthood for the company's founder, Sir [[Clive Sinclair]].