Hand-held calculatorIn 1972, the first scientific hand-held calculatorwas introduced for $395 by Hewlett- Packard, named the HP-35 for having 35 keys. It was the first hand-held calculator able to perform logarithmic and trigonometric functions with one keystroke. The red LED display could give scientific notation up to 10 digits mantissa and 2 digits exponent. The price was reduced several times, eventually to $195. By Feb 1975 (when production of the model was discontinued), 300,000 had been sold. The numbers and functions for calculations were entered in “Reverse Polish Notation”(RPN), which used an “ENTER”key but needed no parentheses or “=”key. It ran on rechargeable batteries and had electronics with several integrated circuits in a 79 ×147×34 mm (3.1" x 5.8" x 1.4") case.« |
