Sinclair ZX81

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The ZX81 was launched on 5th March 1981 by Clive Sinclair as the successor to the ZX80, with a larger memory and improved mathematical functions. It was available ready-built (£69.95) or in kit form (£49.95). It was extremely popular due to its low cost and relative power, and as a result was well supported with software and peripherals by both Sinclair and other companies. The ZX81 was also extensively used in schools and colleges for educational purposes, many people working in the computer industry today had their first computer experiences with the ZX81. It was also the first mass-market home computer that was available to buy in high street shops like W.H. Smiths.

In the advertising of the ZX81, Sinclair boasted that the higher specification and lower price were a result of design. The ZX80 had reduced the chips in a working computer from around 40, to 21. The ZX81 then reduced that number to 4. The ZX81 was based around the Z-80A CPU which ran at 3.5MHz. It came with 1K of RAM, and 8K of ROM providing a simple BASIC interpreter. The other chip was an uncommitted logic array (ULA) chip from Ferranti which Sinclair advertised as their unique, custom-built, "master chip" which replaced 18 ZX80 chips. 

The RAM could be expanded externally to 16K with the 16K-byte RAM pack. The memory can be expanded externally to a maximum 64K, although this replaces rather than supplements the on-board memory. With only 1K of RAM and 8K of ROM, the ZX81 was not capable of colour graphics. However, it did not stop the sales of this machine, which sold over 1.5 million units.

The case was designed by Rick Dickinson, the in-house industrial designer at Sinclair Research Ltd. In 1981 the ZX81 won a British Design award. The computer was physically quite small measuring 167mm deep by 40mm high. The slim plastic case included a membrane keyboard and a single circuit board. The entire machine weighs just 350 grams.

In an Electronics Times article from 18 February 1982 it writes "The ZX81 is selling at the rate of 60,000 a month, two thirds for export, and Timex is producing one every 10 seconds at its Dundee plant. Sinclair said he had sold more than 300,000 units, making it the biggest selling personal computer.'

The ZX81's successor, the ZX Spectrum, was released in April 1982. The ZX81 was discontinued in 1984.

Manufacturer: Sinclair
Date: 1981

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Sinclair ZX81 Articles:

Item Manufacturer Date
Memories - Learning with the ZX81 Unknown
Sinclair ZX81 - Review Jun 1981

Magazines RELATED to Sinclair ZX81 in our Library

Item Manufacturer Date
Input - Issue 1 Unknown
Input - Issue 2 Marshall Cavendish Unknown
Sinclair User January 1986 EMAP Business & Computer Publications Unknown
Personal Computer World - June 1981 Jun 1981
Personal Computer World - July 1981 Jul 1981
Personal Computer World - November 1981 Nov 1981
Personal Computer World - January 1982 1 Jan 1982
Practical Electronics April 1982 Apr 1982
ZX Computing Summer 1982 May 1982
Personal Computer World - August 1982 Aug 1982
Personal Computer World - September 1982 1 Sep 1982
Computer and Video Games - September 1983 1 Sep 1983
Sinclair User November 1983 EMAP Business & Computer Publications Nov 1983
Personal Computer World - December 1983 Dec 1983
The War Machine Issue No. 24 - January/February 1984 Jan 1984
Electronics & Wireless World May 1984 May 1984

Other Systems Related To Sinclair ZX81:

Item Manufacturer Date
Prototype of MK14 Sinclair 1977
Science of Cambridge MK 14 + Original Keyboard Sinclair 1977
Science of Cambridge MK 14 - Original Kit Sinclair 1977
Science of Cambridge MK14 + Memory Expansion in wooden case Sinclair 1977
Science of Cambridge MK14 Sinclair 1977
Sinclair ZX80 8K Basic Sinclair 1980
Sinclair ZX81 with Basic EPROM Sinclair 1980
Sinclair ZX80 Prototype PDZ 4732 Basic ROM - Nine Tiles Sinclair 1980
Sinclair ZX80 Updated to ZX81 Sinclair 1980
Sinclair ZX80 Sinclair 1st June 1980
Sinclair ZX81 Kit Sinclair 1981
Sinclair ZX Spectrum Prototype Sinclair 1981
Sinclair ZX81 - Signed by Rick Dickinson Sinclair 5th March 1981
Sinclair ZX81 with Custom Case/Keyboard Sinclair 5th March 1981
Argentinian Sinclair Spectrum Sinclair 1982
Sinclair Spectrum with Homemade Keyboard Sinclair 1982
White Replica ZX Spectrum (Millionth Edition) Sinclair 1982
Early Sinclair ZX Spectrum Computer Sinclair 1982
Timex Sinclair 1000 Sinclair 1982
Sinclair ZX Spectrum Console Sinclair 1982
ZX Spectrum Issue 2 With ULA Modification Sinclair 1982
Timex Sinclair 1500 Sinclair 1982
Sinclair ZX Spectrum 48K (BBC) Sinclair 1st March 1982
Sinclair ZX Spectrum Case (Signed) Sinclair 1st March 1982
Sinclair ZX Spectrum Computer - Early Issue Sinclair 23rd April 1982
Sinclair ZX Spectrum 48k Sinclair 23rd April 1982
Sinclair ZX Spectrum 16K Sinclair 23rd April 1982
Sinclair Spectrum (Assembled in Portugal) Sinclair 1983
Sinclair QL + Schön Keyboard Sinclair 1984
Sinclair QL (German) Sinclair 1984
Sinclair QL (Signed) Sinclair 1984
Sinclair QL (US) Sinclair 1984
Sinclair QL (Property of Sinclair) Sinclair 1984
Sinclair QL Sinclair 1984
Sinclair ZX Spectrum+ Sinclair 1st June 1984
Sinclair ZX Spectrum +2 Sinclair 1986
Sinclair ZX Spectrum 128 Sinclair January 1986
Cambridge Z88 All In One Pack Sinclair 1987
Sinclair ZX Spectrum +3 (Currys Box) Sinclair 1st June 1987
Sinclair ZX Spectrum +3 Sinclair 1st June 1987
Sinclair PC200 Sinclair 1988
Cambridge Z88 With PC Link Kit Sinclair 1988
SJL 68008-PC Sinclair 1988

This exhibit has a reference ID of CH184. Please quote this reference ID in any communication with the Centre for Computing History.


Sinclair ZX81

  Book Archive   [26]
  Games Archive   [104]
  Software Archive   [36]
  Type-in Listings   [18]
  Peripherals   [25]
  Promotional Items   [7]

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Sinclair ZX81 - Review
Memories - Learning with the ZX81

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