The Sinclair ZX81 is an early home computer released in 1981 by Sinclair Research. It was known for its compact size and affordability, making it accessible to many users. The ZX81 featured a Z80 microprocessor and came with 1KB of RAM, which could be expanded. It used a simple keyboard and displayed graphics on a television screen. The ZX81 was popular for programming and gaming, supporting the BASIC programming language. Its low cost and ease of use contributed to the rise of home computing in the early 1980s, influencing later models like the Sinclair ZX Spectrum.