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The HP-35 was Hewlett-Packard's first pocket calculator and the world's first ''scientific'' pocket calculator (a calculator with trigonometric and exponential functions). Like some of HP's desktop calculators, it used Reverse Polish Notation (RPN). Introduced at US$395,〔$395 in 1972 ≈ $2,141.93 in 2012 (see (Inflation Conversion Factors for Dollars ))〕 the HP-35 was available from 1972 to 1975. Market studies had shown no market for pocket sized calculators at the anticipated price. In about 1970 HP co-founder Bill Hewlett challenged his co-workers to create a "shirt-pocket sized HP-9100". About twelve HP-35 portable calculators were made as a "hack" by and for other engineers at HP. It is rumored that the development engineer got carried away and included a full suite of scientific functions to satisfy requests from his co-workers. When these prototypes proved popular, HP decided to turn the HP-35 into a commercial product. The HP-35 was the first calculator with a full suite of trigonometric and transcendental functions. In the first months orders were exceeding HP's expectations as to the entire market size, which was 10,000 units per year. Before the HP-35, the only practical portable devices for performing trigonometric and exponential functions were slide rules. Existing pocket calculators at the time were only four-function, ''i.e.'', they could only perform addition, subtraction, multiplication, and division. It had been originally known simply as "The Calculator", but Hewlett suggested that it be called the HP-35, because it had 35 keys. On July 12, 2007 HP announced the release of the "retro"-look HP 35s in commemoration of the original HP-35. The HP-35 was named an IEEE Milestone in 2009. ==Description== The calculator used a traditional floating decimal display for numbers that could be displayed in that format, but automatically switched to scientific notation for other numbers. The fifteen-digit LED display was capable of displaying a ten-digit mantissa plus its sign and a decimal point and a two-digit exponent plus its sign. The display used a unique form of multiplexing, illuminating a single LED segment at a time rather than a single LED digit, because HP research had shown that this method was perceived by the human eye as brighter for equivalent power. Light emitting diodes were relatively new at the time and were much dimmer than high efficiency diodes developed in subsequent decades. The calculator used three "AA"-sized NiCd batteries assembled into a removable proprietary battery pack. Replacement battery packs are no longer available, leaving existing HP-35 calculators to rely on AC power, or their users to rebuild the battery packs themselves using available cells. An external battery charger was available and the calculator could also run from the charger, with or without batteries installed. Internally, the calculator was organized around a serial (one-bit) processor chipset made under contract by Mostek, processing 56-bit floating-point numbers, representing 14-digit BCD numbers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「HP-35」の詳細全文を読む スポンサード リンク
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