HP-55
| Industry | Electronics |
|---|---|
| Founded | January 1, 1939 |
| Founder | Bill Hewlett, Dave Packard |
| Products | Calculators, computers, printers, software |
The HP-55 was launched by Hewlett-Packard in 1975 as an affordable, programmable handheld calculator option positioned below the HP-65. It provided users with twenty storage registers and could hold up to 49 keystroke instructions. Its appearance was similar to the HP-65, incorporating a silver band between the keyboard and display reminiscent of the HP-45, though it featured some different key functions and omitted the magnetic card reader/writer. Consistent with most HP calculators from that period, the HP-55 utilized Reverse Polish Notation (RPN) along with a four-level automatic operand stack.
A distinctive feature geared towards business applications was its built-in stop-watch function, which could be activated by setting the mode-slider to Timer. Driven by an internal quartz crystal oscillator, this stop-watch achieved timing precision within ±0.01%. The timing output was formatted as Hours, Minutes, and Seconds, and included a dedicated conversion function to translate this into pure Hours, facilitating straightforward use in calculations.
Additionally, the HP-55 offered several conversion functions for quick interchange between Imperial and Metric measurements, increasing its practicality for users operating across different measurement standards.
The calculator’s tapered design was influenced by Bill Hewlett’s requirement that it be compact enough to fit inside a shirt pocket. Extensive documentation accompanied the device, supporting a wide range of applications such as solving differential equations, estimating stock prices, and performing statistical analysis, highlighting its appeal to professional and business-oriented users.
See also
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