HP-55

HP-55
Calculator
The HP-55
Type	Programmable
Introduced	1975
Entry mode	RPN
Display type	Seven-segment display
Display size	10 + 2
Programming
Programming language(s)	RPN key stroke
Other

The HP-55 was a programmable handheld calculator; a lower-cost alternative to the HP-65. Introduced by Hewlett-Packard in 1975, it featured twenty storage registers and room for 49 keystroke instructions. Its outward appearance was identical to the HP-65, except that a few key functions were different and that it did not have a magnetic card reader/writer. Like all Hewlett-Packard calculators of the era and most since, the HP-55 used Reverse Polish Notation (RPN) and a four-level automatic operand stack.

Another feature of the HP-55 was that it officially featured a stop-watch function much similar to the hidden stop-watch function of the earlier HP-45 calculator. This stop-watch function could be accessed by setting the mode-slider to the Timer position. A quartz-crystal inside the calculator provided an accurate timebase, and it was advertised that the timer ran with as little as +/- 0.01% error. The data format used by the stop-watch consisted of a combination of units (Hours, Minutes and Seconds), but the HP-55 featured a special conversion function to convert between this format and a pure unit (Hours). Because of this, data from the stop-watch could easily be used right away in calculations.

The HP-55 also featured several other conversion functions to instantly convert data between the Imperial and Metric systems.

Bill Hewlett's design requirement was that the calculator should fit in his shirt pocket. That is one reason for the tapered depth of the calculator. The documentation for the programs in the calculator is very complete, including algorithms for hundreds of applications, including the solutions of differential equations, stock price estimation, statistics, and so forth.

External links

The HP-55 at an unofficial Hewlett-Packard museum (MyCalcDB).
1975 HP Calculator Christmas Guide
HP-55 page at the unofficial Museum of HP Calculators

Hewlett-Packard calculators

Graphing:	9g 28C 28S 38G 39G 39g+ 39gs 39gII 40G 40gs 48S 48SX 48G 48G+ 48GX 48gII 49G 49g+ 50g Prime Xpander

Scientific programmable:	10C 11C 15C 16C 19C 20S 21S 25 25C 29C 32S 32SII 33C 33E 33s 34C 35s 41C 41CV 41CX 42S 55 65 67 71B 95C 97 97S 9100A 9100B 9805

Scientific non-programmable:	6s 6s Solar 8s 9s 10s 10s+ 21 22S 27 27S 30s 31E 32E 35 45 46 91 300s 300s+

Financial/business:	10B 10bII 10bII+ 12C 12c Platinum 12c Prestige 14B 17B 17BII 17bII+ 18C 19B 19BII 20b 22 27 30b 37E 38C 38E 70 80 81 92

Others:	01 10 CalcPad 100 CalcPad 200 QuickCalc EasyCalc OfficeCalc PrintCalc

Related topics:	RPN RPL PPL FOCAL ALG CAS

This article is issued from Wikipedia - version of the 9/5/2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.

HP-55

See also

External links