Calculator watch financial functions (in the Casio CBA-10). Usually calculator watch operates with eight digits number, however, calculator watch can operate with 6 digits (for example, Casio C-801) or 10 digits (Casio CBA-10) numbers. Calculator watches first appeared in the mid 1970s introduced by Pulsar (1975, then a brand of the Hamilton Watch Company) and Hewlett Packard. Several watch manufacturers have made calculator watches over the years, such as Pulsar and Timex, but the Japanese electronics company Casio produced the largest variety of models. In the mid-1980s, Casio created the Databank calculator watch, which not only performed calculator functions, but also stored
History of science and technology in Japan desktop calculator. The Sharp QT-8D, a desktop calculator released in 1969, was the first calculator to have its logic circuitry entirely implemented with LSI ("large-scale integration") integrated circuits (ICs) based on MOS ("metal-oxide-semiconductor") technology. Upon its introduction, it was one of the smallest electronic calculators ever produced commercially. The first portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". In January 1971, the Sharp EL-8 was close to being a pocket calculator, weighing about one pound, with a vacuum