The ZX81 is a home computer released by Sinclair Research in 1981. It was one of the first affordable personal computers, featuring a compact design and a membrane keyboard. The ZX81 had a Z80 microprocessor and came with 1 KB of RAM, which could be expanded to 16 KB. It used a black-and-white display and connected to a television for output. The ZX81 was popular for its simplicity and low cost, making it accessible to many households. It supported a BASIC programming language, allowing users to create their own software. The computer played a significant role in the early days of home computing in the United Kingdom.