The HP-27 was a hand-held scientific and financial, but not programmable, calculator made by Hewlett-Packard between 1976 and 1978.
The Hewlett-Packard Company or Hewlett-Packard was an American multinational information technology company headquartered in Palo Alto, California. It developed and provided a wide variety of hardware components as well as software and related services to consumers, small- and medium-sized businesses (SMBs) and large enterprises, including customers in the government, health and education sectors.
Unlike all previous HP's pocket calculators, the HP-27 could do mathematic, statistic and business operations. It used Reverse Polish Notation (RPN) for calculations, working on a four-level stack (x,y,z,t). Nearly all keys had two alternate functions, accessed by a yellow and black prefix key. So despite the 30 keys only keyboard it could access about 68 functions. The HP-27 also had a 10-digit red LED display and 10 registers to store numbers.
In computer science, a stack is an abstract data type that serves as a collection of elements, with two principal operations:
A scientific calculator is a type of electronic calculator, usually but not always handheld, designed to calculate problems in science, engineering, and mathematics. They have almost completely replaced slide rules in traditional applications, and are widely used in both education and professional settings.
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.
The HP-65 is the first magnetic card-programmable handheld calculator. Introduced by Hewlett-Packard in 1974 at an MSRP of $795, it featured nine storage registers and room for 100 keystroke instructions. It also included a magnetic card reader/writer to save and load programs. Like all Hewlett-Packard calculators of the era and most since, the HP-65 used Reverse Polish Notation (RPN) and a four-level automatic operand stack.
The HP 33s (F2216A) was a scientific calculator marketed by Hewlett-Packard. It was introduced in 2003 as the successor to the HP 32SII, and discontinued on the introduction of its successor the HP 35s in 2007.
The HP-20S (F1890A) is an algebraic programmable, member of Pioneer series of HP calculators produced from 1988 to 2003. It is similar to HP-21S. It has 99 program lines of fully merged program and ten memory registers.
The HP-27S was a pocket calculator produced by Hewlett-Packard, introduced in 1988, and discontinued between 1990 and 1993. It was the first HP scientific calculator to use algebraic entry instead of RPN, and though it was labelled scientific, it also included features associated with specialised business calculators.
The HP-18C was a Hewlett-Packard business calculator which was quickly followed by the very similar but greatly improved HP-19B. The HP-18C was HP's first RPL-based calculator internally, even though this was not visible on user-level in this non user-programmable model. The user did have a solver available, but only had about 1.5 KB of continuous memory available to store equations.
The HP-22S is an electronic calculator from the Hewlett-Packard company which is algebraic and scientific. This calculator is comparable to the HP-32S. A solver was included instead of programming. It had the same constraints as the 32S, lacking enough RAM for serious use. Functions available include TVM and unit conversions. Only single letter variable names are allowed.
The SR-50 was Texas Instruments' first scientific pocket calculator with trigonometric and logarithm functions. It enhanced their earlier SR-10 and SR-11 calculators, introduced in 1973, which had featured scientific notation, squares, square root, and reciprocals, but had no trig or log functions, and lacked other features. The SR-50 was introduced in 1974 and sold for US$170. It competed with the Hewlett-Packard HP-35.
The Hewlett-Packard Voyager series of calculators were introduced by Hewlett-Packard in 1981. All members of this series are programmable, use Reverse Polish Notation, and feature continuous memory. Nearly identical in appearance, each model provided different capabilities and was aimed at different user markets.
The HP-25 was a hand-held programmable scientific/engineering calculator made by Hewlett-Packard between 1975 and 1978. The HP-25 was introduced as a cheaper alternative to the ground-breaking HP-65.
The HP-16C Computer Scientist is a programmable pocket calculator that was produced by Hewlett-Packard between 1982 and 1989. It was specifically designed for use by computer programmers, to assist in debugging. It is a member of the HP Voyager series of programmable calculators. It was the only programmer's calculator ever produced by HP, though many later HP calculators have incorporated most of the 16C's functions.
The HP-28C and HP-28S were two graphing calculators produced by Hewlett-Packard from 1986 to 1992. The HP-28C was the first handheld calculator capable of solving equations symbolically. They were replaced by the HP 48 series of calculators, which grew from the menu-driven RPL programming language interface first introduced in these HP-28 series.
The HP 35s (F2215A) is a Hewlett-Packard non-graphing programmable scientific calculator. Although it is a successor to the HP 33s, it was introduced to commemorate the 35th anniversary of the HP-35, Hewlett-Packard's first pocket calculator. HP also released a limited production anniversary edition with shiny black overlay and engraving "Celebrating 35 years".
The HP-45 was the second scientific pocket calculator introduced by Hewlett-Packard, adding to the features of the HP-35. It was introduced in 1973 with an MSRP of $395. Especially noteworthy was its pioneering addition of a shift key that gave other keys alternate functions.
A graphing calculator is a class of hand-held calculator that is capable of plotting graphs and solving complex functions. While there are several companies that manufacture models of graphing calculators, Hewlett-Packard is a major manufacturer.
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 similar to the HP-65, but its silver band went through between the display and the keyboard like HP-45, its some key functions were diffent from HP-65 and 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.
The HP-21 was a scientific calculator produced by Hewlett-Packard between 1975 and 1978. It was designed as a replacement for the HP-35, and was one of a set of three calculators, the others being the HP-22 and HP-25, which were similarly built but aimed at different markets.
The HP-22 was a finance-oriented pocket calculator produced by Hewlett-Packard between 1975 and 1978. It was designed as a replacement for the short-lived HP-70, and was one of a set of three calculators, the others being the HP-21 and HP-25, which were similarly built but aimed at different markets.
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