HP-35 Emulator Calculator. 1.0

Some historical curiosities of this calculator are:
- The display of 15 characters in the HP 35, when the reverse was seen, could produce a limited number of alphabetic messages. For example, 710.77345 would read as "SHELL OIL". The sample was probably more extravagant +40 57738.57734 E would be read as "Oh Hells Bells".
- The HP 35 was just 5.8 inches long and 3.2 inches wide. This was the pocket size of William Hewlett, of there as the "pocket calculator".
- The power requirement of the LED display was responsible for the short life between battery charges the HP 35, about three hours. To prolong the operating time and prevent damage from overuse of the slide switch on / off, users could press the decimal point key to force the display to illuminate only a segment of the LED.
- The HP 35 calculated arithmetic functions, logarithmic, and trigonometric, however, full implementation used only 767 carefully chosen instructions (7670 bits), in what is a marvel of concise programming.
- The introduction of the HP 35 scientific calculators and other similar capacity by Texas Instruments soon signaled the end of the slide rule as a status symbol among science and engineering students. The covers of the rules of calculations were disappearing to make way for the covers of the "electronic slide rule", and universities began to abandon the slide rule classes of their curriculum.
- The HP 35 was the beginning of a family of related calculators all sharing similar mechanical packaging:
- The screen was unique in the sense that multiplexing is designed to illuminate only one LED at a time segment, instead of a single-digit LED, because HP investigations had shown that this method was perceived by the human eye as more Bright energy equivalent.
- The calculator used three NiCd batteries "AA" assembled in a removable battery pack, owner of HP design. Battery packs and replacement are unavailable, leaving 35 HP depending existing alternating current, or the users must rebuild the battery pack using batteries themselves available. An external battery charger was available and could also function calculator from charger, with or without batteries installed.
Internally, the calculator was organized around a serial processor chipset (a bit) floating point number processing 56-bit, 14-digit numbers representing BCD.
It was introduced at a price of U.S. $ 395.1 and was available from January 4, 1972 to 1975. During that time over 300,000 units sold.
Before the HP 35, the only practical portable devices to perform trigonometric and exponential functions were slide rules. At that time, existing pocket calculators had only four functions, ie could only add, subtract, multiply and divide. Originally it had been known simply as "The Calculator", but Hewlett suggested that it should be called the HP 35 because it had 35 keys.

HP 35 was developed in two years, HP 35 was released in 1972.