Answer: Calculators

The first commercial microprocessors were a simple but revolutionary bit of computational and engineering magic. Unlike the single integrated circuits that preceded them, microprocessors were self-contained computational devices. Prior to the introduction of the first commercial microprocessor—the Intel 4004 in 1971—it was necessary to “build out” computers by laying out dozens (if not hundreds) of individual integrated circuits on large circuit boards. Because of the space consumed and heat generated, early computers were expensive to build and difficult to keep cool. The advent of the commercial microprocessor opened a veritable flood gate of development and innovation; computing processes that previously required spacious circuit boards could be packed efficiently and cheaply into discrete and easy to cool chips.

The first commercial application of this revolutionary invention was, rather practically, a calculator. What’s even more notable about the first applied use of the microprocessor is that the company behind the calculator it powered was also responsible for its very existence. In 1969, Busicom, a Japanese calculator company, approached Intel with a calculator design focused on maximizing computational power while minimizing the number of required integrated circuits.

Engineers from both companies began collaborating on the design, further refining it to use fewer and fewer individual integrated circuits. While working on the project, Intel engineers Ted Hoff, Federico Faggin, and Stanley Mazor, along with Busicom engineer Masatoshi Shima, created the prototype that would become the Intel 4004. Within a decade of that first commercial use, the microprocessor had found its way into everything from hand-held games to missile control systems and sparked a technological revolution in the process.