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Sinclair ZX Spectrum (16K/48K) All Issues

Developer Sinclair Research
Release date April 23, 1982
Discontinued 1992
Type Home Computer
Operating system Sinclair BASIC
CPU Z80 @ 3.5 MHz and equivalent
Memory 16 KB / 48 KB
Display 32 x 22 character text display
256 x 192 pixel resolution
8 colours
Sound 1 channel, 5 octaves
I/O Z80 bus, tape, RF television
Storage External tape recorder or microdrives
Predecessor ZX81
Successor Sinclair QL

Sinclair ZX80

Developer Science of Cambridge (renamed to Sinclair Computers Ltd in November in 1979)
Type Home Computer
Operating system Sinclair BASIC
CPU Z80 @ 3.25 MHz (most machines used the NEC μPD780C-1 equivalent)
Memory 4K ROM, 1K RAM (externally expandable to 16K)
Display 24 lines x 32 character text display
Monochrome only
Sound None
I/O Z80 bus, 250 baud cassette interface, RF television out
Storage External cassette recorder
Successor ZX81
Highlights Very slow program execution - no video chips, the CPU performs all of the computer functions
The keyboard is a membrane-type, a flat plastic surface which is difficult to use and wears-out rather quickly.
There was an upgrade kit to the ZX81 as can be seen in the last photo.

Sinclair ZX Spectrum (16K/48K) - Issue 2-6

Developer Sinclair Research
Release date April 23, 1982
Discontinued 1992
Type Home Computer
Operating system Sinclair BASIC
CPU Z80 @ 3.5 MHz and equivalent
Memory 16 KB / 48 KB
Display 32 x 22 character text display
256 x 192 pixel resolution
8 colours
Sound 1 channel, 5 octaves
I/O Z80 bus, tape, RF television
Storage External tape recorder or microdrives
Predecessor ZX81
Successor Sinclair QL

Sinclair ZX81

Developer Sinclair Research
Manufacturer Timex Corporation
Release date 5 March 1981
Discontinued 1984
Type Home Computer
Predecessor ZX80
Successor ZX Spectrum
Operating system Sinclair BASIC
CPU Z80 at 3.25 MHz
Storage capacity External cassette tape recorder at 250 baud
Memory 1 KB (64 KB max. 56 KB usable)
Display Monochrome display on UHF television
Graphics 24 lines x 32 characters or
64 x 48 pixels graphics mode
Highlights The computer is composed of only four IC chips, and there are no video chips or co-processors. The CPU has to perform all of the tasks that are required of a computer, which means it executes the BASIC program and updates the screen at the same time, slowing the program speed. The fix? Don't update the display as often - the SLOW and FAST commands determine the video display rate. The FAST command allows the program to run 4X faster, but then the display gets jerky.
Other models Timex Sinclair 1000, 1982, sold by Timex in USA
Timex Sinclair 1500, 1983, sold by Timex in USA, stop-gap between the TS 1000 and the forthcoming American version of the Spectrum, the TS 2000 (never released). It was a ZX81 with an internally housed 16K RAM expansion module, in a black and silver Spectrum-style box with the familiar "dead flesh" rubber keyboard. The updating of the ZX81 design was an attempt to counter the two biggest drawbacks of the TS 1000, namely the touch-sensitive keyboard and the minuscule 1K of memory. The machine failed dismally: no matter how much it was dressed up, it was still a ZX81, with most of that machine's limitations still intact.