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 fluorescent display (VFD) and rechargeable NiCad batteries. The EL-8 was the first battery-powered handheld calculator. The concept of a single-chip calculator was conceived by Sharp engineer Tadashi Sasaki in 1968. The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", the first single-chip calculator to be built, released in February 1971. The Busicom 141-PF desktop calculator, released in March 1971, was the first computing machine to use a microprocessor, the 4-bit Intel 4004 (co-designed by Busicom's Masatoshi Shima). In 1971, Tadashi Sasaki began research on the use of LCD displays for calculators at Sharp Corporation. In 1973, Sharp commercially