Sinclair ZX81

The ZX81 was the successor of the ZX80 and one of the cheapest home-computers.
Description
One of the things that made the ZX81 so cheap was the touch-sensitive membrane keyboard. There were only 4 chips (in some ZX81 5 chips) working inside: The CPU, ULA (logic chip), 8 KByte rom and 1 KB ram. There was not a graphic chip so the CPU had to do the job.
The ZX81 was also available as a DIY kit. In some countries the ZX81 was sold as the TS1000.
The keys of the ZX81 had 5 different meanings e.g. if you press 'P' the ZX81 will print 'P' or 'PRINT' depending on the situation the key is pressed. There were two peripherals: A cassetterecorder (not a special one: you could use every walkman) and a special ZX printer. It was necessary to find the right volume for the cassetterecorder to save programs to cassette (it was somewhere in the middle).
Present
Today there are still many ZX81-enthusiasts around the world. In Germany there is a user-club only for the ZX81 and its clones: The ZX-Team. They are still developing new hardware extensions like an adapter for the Commodore 1541-diskdrive, coulour graphic and sound.
The ZX81 is still far better than a PC for people who want to understand how a computer works.
A ZX81 can be updated to the following configuration:
Computer: Sinclair ZX81
Release year:1981
CPU/Clock speed:Z 80A/ca. 3,5 MHz
ROM:8 KByte
RAM (expandable)1 (16) KByte
Display:TV
Text display:32*15
Graphics display:64 *44
Colours:b/w
Sound:none
Keyboard:membrane keyboard,
touch-sensitive
Interfaces:TV
Extension bus
Earphones
Microphones
(both used for
the cassetterecorder)
Operating system:own
Size (in mm)167*175*40
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