Editing Calculator (section)

===Scientific pocket calculators===
{{main|Scientific calculator}}
Meanwhile, [[Hewlett-Packard]] (HP) had been developing a pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with ''scientific'' functions that could replace a [[slide rule]]. The $395 [[HP-35]], along with nearly all later HP engineering calculators, uses [[reverse Polish notation]] (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing {{key top|8}}, {{key top|Enter↑}}, {{key top|5}}, and {{key top|+}}; instead of the algebraic [[infix notation]]: {{key top|8}}, {{key top|+}}, {{key top|5}}, {{key top|{{=}}}}. It had 35 buttons and was based on Mostek Mk6020 chip.

The first Soviet ''scientific'' pocket-sized calculator the "B3-18" was completed by the end of 1975.

In 1973, [[Texas Instruments]] (TI) introduced the [[TI SR-10|SR-10]], (''SR'' signifying [[slide rule]]) an ''algebraic entry'' pocket calculator using [[scientific notation]] for $150. Shortly after the [[TI SR-11|SR-11]] featured an added key for entering [[pi]] (π). It was followed the next year by the [[TI SR-50|SR-50]] which added log and trig functions to compete with the HP-35, and in 1977 the mass-marketed [[TI-30]] line which is still produced.

In 1978, a new company, [[Calculated Industries]] arose which focused on specialized markets. Their first calculator, the Loan Arranger<ref>{{cite web |url=http://mathcs.albion.edu/~mbollman/CI/loanarranger2.htm |title=The Loan Arranger II |website=Mathcs.albion.edu |access-date=2011-07-19 |url-status=live |archive-url=https://web.archive.org/web/20110719134735/http://mathcs.albion.edu/~mbollman/CI/loanarranger2.htm |archive-date=2011-07-19 }}</ref> (1978) was a pocket calculator marketed to the Real Estate industry with preprogrammed functions to simplify the process of calculating payments and future values. In 1985, CI launched a calculator for the construction industry called the Construction Master<ref>{{cite web |url=http://mathcs.albion.edu/~mbollman/CI/CM.htm |title=Construction Master |website=Mathcs.albion.edu |access-date=2011-07-19 |url-status=live |archive-url=https://web.archive.org/web/20110719135006/http://mathcs.albion.edu/~mbollman/CI/CM.htm |archive-date=2011-07-19 }}</ref> which came preprogrammed with common construction calculations (such as angles, stairs, roofing math, pitch, rise, run, and feet-inch fraction conversions). This would be the first in a line of construction related calculators.

<gallery widths="200px" heights="200px">
File:Calculator Adler 81S.jpg|Adler 81S pocket calculator with [[vacuum fluorescent display]] (VFD) from the mid-1970s.
File:Casio cm602.jpg|The Casio CM-602 Mini electronic calculator provided basic functions in the 1970s.
File:SinclairExecutive-01.jpg|The 1972 [[Sinclair Executive]] pocket calculator.
File:HP-35 Red Dot.jpg|The [[HP-35]], the world's first scientific pocket calculator by Hewlett Packard (1972).
File:Canon Pocketronic.jpg|Canon Pocketronic calculator prints output using paper tape (1971).
</gallery>

====Programmable pocket calculators====
The first programmable pocket calculator was the [[HP-65]], in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. Two years later the [[HP-25C]] introduced ''[[continuous memory]]'', i.e., programs and data were retained in [[CMOS]] memory during power-off. In 1979, HP released the first ''[[alphanumeric]]'', programmable, ''expandable'' calculator, the [[HP-41]]C. It could be expanded with [[random-access memory]] (RAM, for memory) and [[read-only memory]] (ROM, for software) modules, and peripherals like [[bar code]] readers, [[microcassette]] and [[floppy disk]] drives, paper-roll [[thermal printer]]s, and miscellaneous communication interfaces ([[RS-232]], [[HP-IL]], [[HP-IB]]).
[[File:HP-65 white background.jpg|thumb|left|The [[HP-65]], the first programmable pocket calculator (1974)]]
The first Soviet pocket battery-powered programmable calculator, [[Elektronika]] ''[[B3-21]]'', was developed by the end of 1976 and released at the start of 1977.<ref>{{cite web |title=Elektronika B3-21 |website=www.rskey.org |url=http://www.rskey.org/b3-21 |access-date=2023-06-07 |archive-date=2015-07-03 |archive-url=https://web.archive.org/web/20150703003847/http://www.rskey.org/b3-21 |url-status=live}}</ref> The successor of B3-21, the [[Elektronika B3-34]] wasn't backward compatible with B3-21, even if it kept the [[reverse Polish notation]] (RPN). Thus B3-34 defined a new command set, which later was used in a series of later programmable Soviet calculators. Despite very limited abilities (98 bytes of instruction memory and about 19 stack and addressable registers), people managed to write all kinds of programs for them, including [[adventure game]]s and libraries of calculus-related functions for engineers. Hundreds, perhaps thousands, of programs were written for these machines, from practical scientific and business software, which were used in real-life offices and labs, to fun games for children. The [[Elektronika MK-52]] calculator (using the extended B3-34 command set, and featuring internal [[EEPROM]] memory for storing programs and external interface for EEPROM cards and other periphery) was used in Soviet spacecraft program (for [[Soyuz TM-7]] flight) as a backup of the board computer.

This series of calculators was also noted for a large number of highly counter-intuitive mysterious undocumented features, somewhat similar to "[[synthetic programming]]" of the American [[HP-41]], which were exploited by applying normal arithmetic operations to error messages, jumping to nonexistent addresses and other methods. A number of respected monthly publications, including the popular science magazine ''[[Nauka i Zhizn]]'' (''Наука и жизнь'', ''Science and Life''), featured special columns, dedicated to optimization methods for calculator programmers and updates on undocumented features for hackers, which grew into a whole esoteric science with many branches, named "[[yeggogology]]" ("еггогология"). The error messages on those calculators appear as a Russian word "YEGGOG" ("ЕГГОГ") which, unsurprisingly, is translated to "Error".

A similar hacker culture in the US revolved around the [[HP-41]], which was also noted for a large number of undocumented features and was much more powerful than [[B3-34]].

====Technical improvements====
[[File:Solar-calculator.jpg|thumb|A calculator which runs on solar and battery power]]
Through the 1970s the hand-held electronic calculator underwent rapid development. The red LED and blue/green [[vacuum fluorescent display]]s consumed a lot of power and the calculators either had a short battery life (often measured in hours, so rechargeable [[nickel-cadmium batteries]] were common) or were large so that they could take larger, higher capacity batteries. In the early 1970s [[liquid-crystal display]]s (LCDs) were in their infancy and there was a great deal of concern that they only had a short operating lifetime. Busicom introduced the Busicom ''LE-120A "HANDY"'' calculator, the first pocket-sized calculator and the first with an LED display, and announced the Busicom ''LC'' with LCD. However, there were problems with this display and the calculator never went on sale. The first successful calculators with LCDs were manufactured by [[Rockwell International]] and sold from 1972 by other companies under such names as: Dataking ''LC-800'', Harden ''DT/12'', Ibico ''086'', Lloyds ''40'', Lloyds ''100'', Prismatic ''500'' (a.k.a. ''P500''), Rapid Data ''Rapidman 1208LC''. The LCDs were an early form using the ''Dynamic Scattering Mode DSM'' with the numbers appearing as bright against a dark background. To present a high-contrast display these models illuminated the LCD using a filament lamp and solid plastic light guide, which negated the low power consumption of the display. These models appear to have been sold only for a year or two.

A more successful series of calculators using a reflective DSM-LCD was launched in 1972 by [[Sharp Inc]] with the Sharp ''EL-805'', which was a slim pocket calculator. This, and another few similar models, used Sharp's ''Calculator On Substrate'' (COS) technology. An extension of one glass plate needed for the liquid crystal display was used as a substrate to mount the needed chips based on a new hybrid technology. The COS technology may have been too costly since it was only used in a few models before Sharp reverted to conventional circuit boards.

[[File:Braun 4856 solar card calculator, 2.jpg|thumb|Credit-card-sized, solar-powered calculator by [[Braun (company)|Braun]] (1987)]]
[[File:Citizen SLD-100NR calculator.jpg|thumb|Modern pocket calculator with solar and battery powering]]
In the mid-1970s the first calculators appeared with field-effect, ''twisted nematic'' (TN) LCDs with dark numerals against a grey background, though the early ones often had a yellow filter over them to cut out damaging [[ultraviolet]] rays. The advantage of LCDs is that they are passive light modulators reflecting light, which require much less power than light-emitting displays such as LEDs or VFDs. This led the way to the first credit-card-sized calculators, such as the [[Casio]] ''Mini Card LC-78'' of 1978, which could run for months of normal use on button cells.

There were also improvements to the electronics inside the calculators. All of the logic functions of a calculator had been squeezed into the first "calculator on a chip" [[integrated circuit]]s (ICs) in 1971, but this was leading edge technology of the time and yields were low and costs were high. Many calculators continued to use two or more ICs, especially the scientific and the programmable ones, into the late 1970s.

The power consumption of the integrated circuits was also reduced, especially with the introduction of [[CMOS]] technology. Appearing in the Sharp "EL-801" in 1972, the [[transistor]]s in the logic cells of CMOS ICs only used any appreciable power when they changed state. The LED and [[Vacuum fluorescent display|VFD]] displays often required added driver transistors or ICs, whereas the LCDs were more amenable to being driven directly by the calculator IC itself.

With this low power consumption came the possibility of using [[solar cell]]s as the power source, realised around 1978 by calculators such as the Royal ''Solar 1'', Sharp ''EL-8026'', and Teal ''Photon''.

<gallery widths="200px" heights="200px">
File:CasioFX20-inside.jpg|The interior of a Casio fx-20 scientific calculator from the mid-1970s, using a VFD. The processor integrated circuit (IC) is made by [[NEC]] (marked μPD978C). Discrete electronic components like [[capacitor]]s and [[resistor]]s and the IC are mounted on a [[printed circuit board]] (PCB). This calculator uses a battery pack as a power source.
File:Sharp el-323 ic 1ae.jpg|The processor chip (integrated circuit package) inside a 1980s Sharp pocket calculator, marked SC6762 1•H. An LCD is directly under the chip. This was a PCB-less design. No discrete components are used. The battery compartment at the top can hold two [[button cell]]s. 
File:Casio fx-992VB interior both aa1.JPG|Inside a Casio scientific calculator from the mid-1990s, showing the processor chip (small square; top-middle; left), keypad contacts, right (with matching contacts on the left), the back of the LCD (top; marked 4L102E), battery compartment, and other components. The solar cell assembly is under the chip.
File:Citizen se-733 int 1ac.jpg|The interior of a newer ({{circa|2000}}) pocket calculator. It uses a button battery in combination with a solar cell. The processor is a "Chip on Board" type, covered with dark [[epoxy]].
</gallery>

====Mass-market phase====
At the start of the 1970s, hand-held electronic calculators were very costly, at two or three weeks' wages, and so were a luxury item. The high price was due to their construction requiring many mechanical and electronic components which were costly to produce, and production runs that were too small to exploit [[economies of scale]]. Many firms saw that there were good profits to be made in the calculator business with the margin on such high prices. However, the cost of calculators fell as components and their production methods improved, and the effect of economies of scale was felt.

By 1976, the cost of the cheapest four-function pocket calculator had dropped to a few dollars, about 1/20 of the cost five years before. The results of this were that the pocket calculator was affordable, and that it was now difficult for the manufacturers to make a profit from calculators, leading to many firms dropping out of the business or closing. The firms that survived making calculators tended to be those with high outputs of higher quality calculators, or producing high-specification scientific and programmable calculators.{{Citation needed|date=January 2017}}