Sinclair ZX81 Issue One

The ZX81 was launched on March 5th 1981 by Clive Sinclair.
 
It is commonly considered to be the machine that brought computing to the general public in the United Kingdom as it was affordable at £69.95 and it was the first computer to be available to buy in high street shops like W.H. Smiths.
 
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.
 
With only 1Kb of RAM, and 8Kb of ROM the ZX81 was not capable of colour graphics. However, it didn't stop the sales of this machine which sold over 1.5 million units.
 
Technical Info :
 
The ZX81 came with 1 kB of on-board memory that could be expanded externally to 16 kB. The memory is provided by either a single 4118 (1024 Bit × 8) or two 2114 (1024 Bit × 4) RAM chips. There are only three other chips on board: a 3.5 MHz Z80A 8-bit microprocessor from Nippon Electric (now NEC), an uncommitted logic array (ULA) chip from Ferranti and a 8 kB ROM providing a simple BASIC interpreter. The memory can be expanded externally to a maximum 64 kB, although this replaces rather than supplements the on-board memory.
 

Manufacturer: Sinclair
Date: 5th March 1981



Comment on This Page

Sinclair ZX81 Issue One Articles:

Item Manufacturer Date
ZX81 Memory Expansion Unknown
ZX80/ZX81 16K Byte RAM Pack Sinclair Unknown
Memopak 16K Memotech Unknown
STL Large 16K RAM pack STL Unknown
ZX Panda 16K Expandable RAM for ZX81 Stonechip Electronics Unknown
ZX81 QS-Mother Board Unknown
Sinclair ZX81 QS-Sound Unknown
Cheetah 32K RAM Expansion Cheetah Unknown
ZX81 16K Byte RAM Pack (US) Sinclair Unknown
ZX81 I/O Board Unknown
Memotech ZX81 Keyboard and Buffer Memotech Ltd Unknown
Sinclair ZX Printer Sinclair Unknown
Sinclair Black Watch Sinclair Radionics 1975
Maplin ZX81 Talk Back GB18U Maplins 1979
16k Memory Expansion Sinclair 1981
16k Memory Expansion Sinclair 1981
Memopak 64K Memotech Ltd 1982
Mapsoft Keyboard for ZX81 Stonechip Electronics 1982
Memotech 48k Ram Expansion 1982
Abacus Controller Abacus Electronics 1983
DK'tronics Keyboard for Spectrum DK Tronics Ltd (UK) 1983
ZX81 Push-Button Keyboard Filesixty Ltd 1983
Microcare Powerbase Microbase 1983
Magicbridge 16K RAM Pack Magicdrive Jun 1983

Other Systems Related To Sinclair ZX81 Issue One:

Item Manufacturer Date
Prototype of MK14 Sinclair 1977
Science of Cambridge MK14 + Original Keyboard Sinclair 1977
Science of Cambridge MK14 - Original Kit Sinclair 1977
Science of Cambridge MK14 + Memory Expansion in wooden case Sinclair 1977
Science of Cambridge MK14 Sinclair 1977
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
Sinclair ZX Spectrum Console Sinclair 1982
ZX Spectrum Issue 2 With ULA Modification Sinclair 1982
Timex Sinclair 1500 Sinclair 1982
Sinclair ZX Spectrum Case (Signed) Sinclair 1st March 1982
Sinclair ZX Spectrum 48k Sinclair 1st March 1982
Sinclair ZX Spectrum 16K Sinclair 1st March 1982
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
Sinclair ZX Spectrum 128 Sinclair 1st June 1986
Cambridge Z88 All In One Pack Sinclair 1987
Cambridge Z88 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

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

 

Sinclair ZX81 Issue One

  Book Archive   [13]
  Games Archive   [94]
  Software Archive   [21]
  Peripherals   [22]
  Promotional Items   [5]

Click on the Image(s) For Detail


User Submitted Articles

Article
Memories : Learning with the ZX81


Add Your Article >>>

Help support the museum by buying from the museum shop

View all items

Founding Sponsors
redgate Google ARM Real VNC Microsoft Research
Heritage Lottery Funded
Heritage Lottery Fund
Accredited Museum