Editing Calculator (section)

==History==

===Precursors to the electronic calculator===
{{Main|Mechanical calculator}}
{{See also|Human computer}}

The first known tools used to aid arithmetic calculations were: bones (used to tally items), pebbles, and [[counting board]]s, and the [[abacus]], known to have been used by [[Sumer]]ians and [[Ancient Egypt|Egyptians]] before 2000&nbsp;BC.{{sfnp|Ifrah|2001|p=11}} Except for the [[Antikythera mechanism]] (an "out of the time" [[astronomical]] device), development of computing tools arrived near the start of the 17th century: the [[Sector (instrument)|geometric-military compass]] (by [[Galileo]]), [[logarithm]]s and [[Napier bones]] (by [[John Napier|Napier]]), and the [[slide rule]] (by [[Edmund Gunter]]).{{sfnp|Houston|2023}}

[[File:17th-century-mechanical-calculators.jpg|thumb|17th century mechanical calculators]]
The [[Renaissance]] saw the invention of the [[mechanical calculator]] by [[Wilhelm Schickard]] in 1623,<ref>{{cite web |author=Jim Falk |title=Early Evolution of the Modern Calculator, Part 2. The Modern Era: 4.1 Schickard's Calculating Clock |work=Things that Count |url=http://metastudies.net/pmwiki/pmwiki.php?n=Site.TheModernEpochAndTheEmergenceOfTheModernCalculator |url-status=dead |archive-date=2014-04-16 |archive-url=https://web.archive.org/web/20140416210350/http://metastudies.net/pmwiki/pmwiki.php?n=Site.TheModernEpochAndTheEmergenceOfTheModernCalculator}}</ref> and later by [[Blaise Pascal]] in 1642.<ref>{{harvp|Chapman|1942|pp=508, 509}}; "Pascal's invention of the [[calculating machine]]. Pascal invented his machine just four hundred years ago, as a youth of nineteen. He was spurred to it by sharing the burden of arithmetical labor involved in his father's official work as supervisor of taxes at Rouen. He conceived the idea of doing the work mechanically, and developed a design appropriate for this purpose; showing herein the same combination of pure science and mechanical genius that characterized his whole life. But it was one thing to conceive and design the machine, and another to get it made and put into use. Here were needed those practical gifts that he displayed later in his inventions....<br />
In a sense, Pascal's invention was premature, in that the mechanical arts in his time were not sufficiently advanced to enable his machine to be made at an economic price, with the accuracy and strength needed for reasonably long use. This difficulty was not overcome until well on into the nineteenth century, by which time also a renewed stimulus to invention was given by the need for many kinds of calculation more intricate than those considered by Pascal."</ref> A device that was at times somewhat over-promoted as being able to perform all four [[arithmetic]] operations with minimal human intervention.<ref>{{cite magazine |title=A New Calculator |url=https://books.google.com/books?id=Rf0IAAAAIAAJ&pg=PA100 |magazine=The Gentleman's magazine | year=1857 |volume=202 |page=100 |quote=Pascal and Leibnitz, in the seventeenth century, and Diderot at a later period, endeavored to construct a machine which might serve as a substitute for human intelligence in the combination of figures.}}</ref> [[Pascal's calculator]] could add and subtract two numbers directly and thus, if the tedium could be borne, multiply and divide by repetition. Schickard's machine, constructed several decades earlier, used a clever set of mechanised multiplication tables to ease the process of multiplication and division with the adding machine as a means of completing this operation. There is a debate about whether Pascal or Shickard should be credited as the known inventor of a calculating machine due to the differences (like the different aims) of both inventions.<ref>{{cite web |url=http://metastudies.net/pmwiki/pmwiki.php?n=Site.SchicardvsPascal |author=Jim Falk |title=Schickard versus Pascal - an empty debate? |work=Things that Count |archive-date=2014-04-08 |archive-url=https://web.archive.org/web/20140408215848/http://metastudies.net/pmwiki/pmwiki.php?n=Site.SchicardvsPascal}}</ref> Schickard and Pascal were followed by [[Gottfried Leibniz]] who spent forty years designing a four-operation mechanical calculator, the [[stepped reckoner]], inventing in the process his [[leibniz wheel]], but who couldn't design a fully operational machine.<ref>{{cite journal |last=Ginsburg |first=Jekuthiel |title=Scripta Mathematica |journal=Science |volume=86 |issue=2218 |year=1933 |publisher=Kessinger Publishing, LLC|isbn=978-0-7661-3835-3 |page=149 |pmid=17737911 |doi=10.1126/science.86.2218.13-a |s2cid=28216043 |quote=In 1893, the German calculating machine inventor Arthur Burkhardt was asked to put Leibniz machine in operating condition if possible. His report was favorable except for the sequence in the carry.}}</ref> There were also five unsuccessful attempts to design a calculating clock in the 17th century.<ref>see [[Mechanical calculator#Other calculating machines]]</ref>

[[File:Grant mechanical calculating machine 1877.jpg|thumb|left|The Grant mechanical calculating machine, 1877]]
The 18th century saw the arrival of some notable improvements, first by [[Giovanni Poleni|Poleni]] with the first fully functional calculating clock and four-operation machine, but these machines were almost always ''one of a kind''. [[Luigi Torchi]] invented the first direct multiplication machine in 1834: this was also the second key-driven machine in the world, following that of James White (1822).<ref>{{cite journal |author=Denis Roegel |editor= David Walden |url=https://ieeexplore.ieee.org/document/7763737 |title=Before Torchi and Schwilgué, There Was White |journal=IEEE Annals of the History of Computing |date=October–December 2016 |volume= 38 |issue= 4 |pages=92–93 |doi= 10.1109/MAHC.2016.46 |s2cid= 28873771 |access-date=2018-05-06|url-access=subscription }}</ref> It was not until the 19th century and the [[Industrial Revolution]] that real developments began to occur. Although machines capable of performing all four arithmetic functions existed prior to the 19th century, the refinement of manufacturing and fabrication processes during the eve of the industrial revolution made large scale production of more compact and modern units possible. The [[Arithmometer]], invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold<ref>{{cite web |title=Modèles Payen |website=Arithmometre.org |url=http://www.arithmometre.org/NumerosSerie/PageNumerosSeriePayen.html |access-date=2013-10-03 |archive-url=https://web.archive.org/web/20130521075617/http://www.arithmometre.org/NumerosSerie/PageNumerosSeriePayen.html |archive-date=2013-05-21 |url-status=live}}</ref> plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883) and Felt and Tarrant, the only other competitor in true commercial production, had sold 100 [[comptometer]]s.<ref>{{cite book |last=Felt |first=Dorr E. |year=1916 |title=Mechanical arithmetic, or The history of the counting machine |page=[https://archive.org/details/mechanicalarithm00feltrich/page/n7 4] |publisher=Washington Institute |location=Chicago |url=https://archive.org/details/mechanicalarithm00feltrich |url-status=live |archive-date=2016-07-03 |archive-url=https://web.archive.org/web/20160703013921/https://archive.org/details/mechanicalarithm00feltrich}}</ref>
[[File:EdithClarkeCalculatorUSPatentDrawing.png|thumb|upright|right|Patent image of the Clarke graph-based calculator, 1921]]
It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the [[United States]].

In 1921, [[Edith Clarke]] invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for [[inductance]] and [[capacitance]] in [[power transmission lines]].<ref>{{cite web|last1=Lott|first1=Melissa C.|title=The Engineer Who Foreshadowed the Smart Grid—in 1921|url=https://blogs.scientificamerican.com/plugged-in/the-engineer-who-foreshadowed-the-smart-grid-in-1921/|website=Plugged In|publisher=Scientific American Blog Network|access-date=14 August 2017|language=en|url-status=live|archive-url=https://web.archive.org/web/20170814232626/https://blogs.scientificamerican.com/plugged-in/the-engineer-who-foreshadowed-the-smart-grid-in-1921/|archive-date=14 August 2017}}</ref>

The [[Curta]] calculator was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remains a popular collectable item.

===Development of electronic calculators===
The first [[mainframe computer]]s, initially using [[vacuum tube]]s and later [[transistor]]s in the logic circuits, appeared in the 1940s and 1950s. Electronic circuits developed for computers also had application to electronic calculators.

The [[Casio]] Computer Company, in [[Japan]], released the Model ''14-A'' calculator in 1957, which was the world's first all-electric (relatively) compact calculator. It did not use electronic logic but was based on [[relay]] technology, and was built into a desk. The [[IBM 608]] plugboard programmable calculator was IBM's first all-transistor product, released in 1957; this was a console type system, with input and output on punched cards, and replaced the earlier, larger, vacuum-tube [[IBM 603]]. 
[[File:LED DISP.JPG|thumb|Early calculator [[light-emitting diode]] (LED) display from the 1970s ([[USSR]])]]

In October 1961, the world's first ''all-electronic desktop'' calculator, the British [[Bell Punch]]/Sumlock Comptometer [[Sumlock ANITA calculator|ANITA]] ('''A''' '''N'''ew '''I'''nspiration '''T'''o '''A'''rithmetic/'''A'''ccounting) was announced.<ref>{{cite magazine |title=Simple and Silent |magazine=Office Magazine |date=December 1961 |page=1244}}</ref><ref>{{cite magazine |title='Anita' der erste tragbare elektonische Rechenautomat |trans-title='Anita' the first portable electronic computer |magazine=Büromaschinen Mechaniker |date=November 1961 |page=207}}</ref> This machine used [[vacuum tube]]s, cold-cathode tubes and [[Dekatron]]s in its circuits, with 12 cold-cathode [[Nixie tube|"Nixie"]] tubes for its display. Two models were displayed, the Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication, and was soon dropped in favour of the simpler Mark VIII. The ANITA had a full keyboard, similar to mechanical [[comptometer]]s of the time, a feature that was unique to it and the later [[Sharp Corporation|Sharp]] CS-10A among electronic calculators. The ANITA weighed roughly {{convert|33|lb|kg}} due to its large tube system.<ref>{{cite web|last1=Ball |first1=Guy |last2=Flamm |first2=Bruce |date=1996 |title=The History of Pocket Electronic Calculators |url=http://www.vintagecalculators.com/html/history_of_electronic_calculat.html |website=Vintage Calculators Web Museum |access-date=8 July 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140703140814/http://vintagecalculators.com/html/history_of_electronic_calculat.html |archive-date=3 July 2014}}</ref> Bell Punch had been producing key-driven mechanical calculators of the comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British [[Pilot ACE]] computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick.

The tube technology of the ANITA was superseded in June 1963 by the U.S. manufactured [[Friden, Inc.|Friden]] EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a {{convert|5|in|cm|adj=on}} [[cathode-ray tube]] (CRT), and introduced [[Reverse Polish Notation]] (RPN) to the calculator market for a price of $2200, which was about three times the cost of an electromechanical calculator of the time. Like Bell Punch, Friden was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor electronic calculators were introduced: [[Sharp Corporation|Sharp]] introduced the [[CS-10A]], which weighed {{convert|25|kg|lb}} and cost 500,000 yen (${{To USD|500000|JPN}}), and [[Industria Macchine Elettroniche]] of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at the same time). The [[Victor 3900]] was the first to use [[integrated circuit]]s in place of individual [[transistor]]s, but production problems delayed sales until 1966.

[[File:Elka-22 (I197211).png|thumb|The Bulgarian [[ELKA 22]] from 1967]]
There followed a series of electronic calculator models from these and other manufacturers, including [[Canon Inc.|Canon]], [[Mathatronics]], [[Olivetti]], [[SCM Corporation|SCM]] (Smith-Corona-Marchant), [[Sony]], [[Toshiba]], and [[Wang Laboratories|Wang]]. The early calculators used hundreds of [[Bipolar junction transistor#Germanium transistors|germanium transistors]], which were cheaper than [[Transistor#Semiconductor material|silicon transistor]]s, on multiple circuit boards. Display types used were CRT, cold-cathode [[Nixie tube]]s, and [[filament lamp]]s. Memory technology was usually based on the [[delay-line memory]] or the [[magnetic-core memory]], though the Toshiba "Toscal" BC-1411 appears to have used an early form of [[dynamic RAM]] built from discrete components. Already there was a desire for smaller and less power-hungry machines.

[[People's Republic of Bulgaria|Bulgaria's]] [[ELKA#ELKA 6521|ELKA 6521]],<ref name="elka">{{cite web |title=Българските електронни калкулатори ЕЛКА |url=http://clockwiser.wordpress.com/2012/01/10/elka-hist/ |trans-title=The Bulgarian ELKA electronic calculators |language=bg |archive-url=https://web.archive.org/web/20131023023224/http://clockwiser.wordpress.com/2012/01/10/elka-hist/ |archive-date=2013-10-23 |url-status=live |website=The Clockwiser's Collections |date=10 January 2012 |access-date=1 Oct 2013}}</ref><ref>{{cite web |url=http://clockwiser.files.wordpress.com/2012/01/elka6521.jpg |title=ELKA 6521 (photo) |url-status=live |archive-url=https://web.archive.org/web/20131023023226/http://clockwiser.files.wordpress.com/2012/01/elka6521.jpg |archive-date=2013-10-23 |access-date=1 October 2013 |website=The Clockwiser's Collections}}</ref> introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in [[Sofia]]. The name derives from '''''EL'''ektronen '''KA'''lkulator'', and it weighed around {{cvt|8|kg|lb}}. It is the first calculator in the world which includes the [[square root]] function. Later that same year were released the [[ELKA 22]] (with a luminescent display)<ref name="elka"/><ref>{{cite web |url=http://clockwiser.files.wordpress.com/2012/01/elka22-2.jpg |title=ELKA 22 (photo) |url-status=live |archive-url=https://web.archive.org/web/20131023023227/http://clockwiser.files.wordpress.com/2012/01/elka22-2.jpg |archive-date=2013-10-23 |website=The Clockwiser's Collections |access-date=1 Oct 2013}}</ref><ref>{{cite web |url=http://rk86.com/frolov/elka22.htm |title=ELKA 22, Bulgarian Calculator |access-date=1 Oct 2013 |url-status=dead |archive-date=2015-05-26 |archive-url=https://web.archive.org/web/20150526055144/http://rk86.com/frolov/elka22.htm}}</ref> and the ELKA 25, with an built-in printer. Several other models were developed until the first pocket model, the [[ELKA 101]], was released in 1974. The writing on it was in [[Roman script]], and it was exported to western countries.<ref name="elka"/><ref>{{cite web |url=http://clockwiser.wordpress.com/2012/01/10/elka-101-135-series/|title=Elka 101-135 series (photo) |archive-url=https://web.archive.org/web/20131023023222/http://clockwiser.wordpress.com/2012/01/10/elka-101-135-series/ |archive-date=2013-10-23 |url-status=live |website=The Clockwiser's Collections |date=10 January 2012 |access-date=1 Oct 2013}}</ref><ref>{{cite web |url=http://clockwiser.files.wordpress.com/2012/01/elka100-series.jpg |title=Elka 100 series (photo) |archive-url=https://web.archive.org/web/20131023023229/http://clockwiser.files.wordpress.com/2012/01/elka100-series.jpg |archive-date=2013-10-23 |url-status=live |website=The Clockwiser's Collections |access-date=1 Oct 2013}}</ref><ref>{{cite web |website=Vintage Calculators Web Museum |url=http://www.vintagecalculators.com/html/elka_101.html |access-date=1 Oct 2013 |title=ELKA 101 |archive-url=https://web.archive.org/web/20131016092534/http://www.vintagecalculators.com/html/elka_101.html |archive-date=2013-10-16 |url-status=live}}</ref>

====Programmable calculators====
{{Main|Programmable calculator}}
[[File:Olivetti Programma 101 - Museo scienza e tecnologia Milano.jpg|thumb|left|The Italian [[Programma 101]], an early commercial programmable calculator produced by [[Olivetti]] in 1964]]

The first desktop ''programmable calculators'' were produced in the mid-1960s. They included the [[Mathatronics Mathatron]] (1964) and the [[Olivetti]] [[Programma 101]] (late 1965) which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators.<ref>{{cite web| url= https://www.oldcalculatormuseum.com/c-programma101.html| title=Olivetti Programma 101 Electronic Calculator |website=The Old Calculator Web Museum}}</ref><ref name="oldcalculatormuseum.com">{{cite web| url=https://www.oldcalculatormuseum.com/c-math8-48m.html| title=Mathatronics Mathatron 8-48M Mod II Electronic Calculator |website=The Old Calculator Web Museum}}</ref> Both could be programmed by the end user and print out their results. The Programma 101 saw much wider distribution and had the added feature of offline storage of programs via magnetic cards.<ref name="oldcalculatormuseum.com"/>

Another early programmable desktop calculator (and maybe the first Japanese one) was the [[Casio]] (AL-1000) produced in 1967. It featured a [[nixie tube]]s display and had transistor electronics and ferrite core memory.<ref>{{Cite web |title=Casio AL-1000 calculator |place=Australia |publisher=Museum of Applied Arts & Sciences |url=https://ma.as/365845 |access-date=8 June 2023}}</ref>

The ''[[Monroe Epic]]'' programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only ''branch'' instruction was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any [[conditional branch]] (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer.

The first Soviet programmable desktop calculator [[ISKRA 123]], powered by the power grid, was released at the start of the 1970s.

===1970s to mid-1980s===
<!-- Deleted image removed: [[File:Casio as-a ckt1 1c.jpg|thumb|Internal circuit with twelve Nixie tube display elements inside a 1960s desktop calculator]] -->
The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of [[transistor]]s on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer [[integrated circuit]]s (chips) and calculator electronics was one of the leading edges of [[semiconductor]] development. U.S. semiconductor manufacturers led the world in [[Integrated circuit#SSI, MSI and LSI|large scale integration]] (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: [[Canon Inc.]] with [[Texas Instruments]], [[Hayakawa Electric]] (later renamed [[Sharp Corporation]]) with North-American Rockwell Microelectronics (later renamed [[Rockwell International]]), [[Busicom]] with [[Mostek]] and [[Intel]], and [[General Instrument]] with [[Sanyo]].

===Pocket calculators===
{{Redirect|Pocket calculator|the song|Computer World}}
[[File:2010 CURTA-Calculator 08.jpg|alt=A person's hand is holding a small, metallic cylinder with a crank sticking out. |thumb|[[curta|The first pocket calculator]] used a crank instead of electronics.<ref name="FirstPocketCalculator" />]]
Released in 1947, the first pocket calculator which could perform the four basic arithmetic functions with digital precision was the [[Curta]], a mechanical device operated by a crank, bearing “an uncanny resemblance to a pepper grinder”.<ref name="FirstPocketCalculator" /> The readout was digital with eleven digits of precision. For comparison, the contemporaneous [[Slide rule|ten inch slide rule]] used analog calculation to approximate answers to only four digits of precision.<ref>{{Cite book |last1=Harris |first1=Charles Overton |url=https://catalog.hathitrust.org/Record/005735914 |title=Slide rule simplified |last2=American Technical Society. |publisher=American technical society |year=1944 |location=Chicago}}</ref> The Curta remained the finest pocket calculator available for a quarter of a century.<ref name="FirstPocketCalculator">{{Cite journal |last=Stoll |first=Cliff |date=2004 |title=the Curious History of the First Pocket Calculator |url=https://www.jstor.org/stable/26172659 |journal=Scientific American |volume=290 |issue=1 |pages=92–99 |doi=10.1038/scientificamerican0104-92 |jstor=26172659 |pmid=14682043 |bibcode=2004SciAm.290a..92S |issn=0036-8733|url-access=subscription }}</ref>

By 1970, a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. {{anchor|Cal Tech}}The first handheld calculator was a 1967 prototype called '''''Cal Tech''''', whose development was led by [[Jack Kilby]] at [[Texas Instruments]] in a research project to produce a portable calculator. It could add, multiply, subtract, and divide, and its output device was a paper tape.<ref>{{cite web |website=Education Technology |date=15 August 2002 |url=http://education.ti.com/educationportal/sites/US/nonProductSingle/about_press_release_news37.html |title=Texas Instruments Celebrates the 35th Anniversary of Its Invention of the Calculator |url-status=dead |archive-url=https://web.archive.org/web/20080627144010/http://education.ti.com/educationportal/sites/US/nonProductSingle/about_press_release_news37.html |archive-date=2008-06-27 |publisher=[[Texas Instruments]]}}</ref><ref>{{cite web |url=https://www.npr.org/templates/story/story.php?storyId=14845433 |title=Electronic Calculator Invented 40 Years Ago |url-status=live |archive-url=https://web.archive.org/web/20081205151504/http://www.npr.org/templates/story/story.php?storyId=14845433 |archive-date=2008-12-05 |work=All Things Considered |publisher=NPR |date=30 September 2007}} Audio interview with one of the inventors.</ref><ref>{{cite news |title=50 Jahre Taschenrechner – Die Erfindung, die niemand haben wollte |language=de |trans-title=50th anniversary of calculators – the invention not wanted by anyone |work=[[Frankfurter Allgemeine Zeitung]] (FAZ) |date=2017-03-27 |url=https://www.faz.net/aktuell/wirtschaft/wirtschaftswissen/50-jahre-taschenrechner-die-erfindung-die-niemand-haben-wollte-14944569.html |access-date=2017-03-30 |archive-url=https://web.archive.org/web/20170329202602/https://www.faz.net/aktuell/wirtschaft/wirtschaftswissen/50-jahre-taschenrechner-die-erfindung-die-niemand-haben-wollte-14944569.html |archive-date=2017-03-29 |url-status=live}}</ref><ref>{{cite magazine |last=May |first=Mike |title=How the Computer Got Into Your Pocket |magazine=[[American Heritage of Invention & Technology]] |date=Spring 2000 |volume=15 |issue=4 |pages=42–54 |url=https://www.dropbox.com/s/bwwc9q3y090d2r8/How_the_Computer_Got_Into_Your_Pocket.pdf |access-date=2017-03-30}}</ref><ref>{{cite magazine |title=The Texas Edison |author-first=T. R. |author-last=Reid |magazine=[[Texas Monthly]] |date=July 1982}}</ref><ref>{{cite magazine |title=The First Handheld Digital Calculator Celebrates 50 Years |url=http://electronicdesign.com/analog/first-handheld-digital-calculator-celebrates-50-years-part-1 |archive-url=https://web.archive.org/web/20170413153616/http://electronicdesign.com/analog/first-handheld-digital-calculator-celebrates-50-years-part-1 |archive-date=2017-04-13 |url-status=live |date=2017-03-27 |magazine=Electronic Design |first=Thomas |last=Okon}}</ref> As a result of the "Cal-Tech" project, Texas Instruments was granted master patents on portable calculators.{{efn|The Japanese Patent Office granted a patent in June 1978 to Texas Instruments (TI) based on US patent 3819921, notwithstanding objections from 12 Japanese calculator manufacturers. This gave TI the right to claim royalties retroactively to the original publication of the Japanese patent application in August 1974. A TI spokesman said that it would actively seek what was due, either in cash or technology cross-licensing agreements. 19 other countries, including the United Kingdom, had already granted a similar patent to Texas Instruments.<ref>{{Cite journal |date=August 17, 1978 |title=New from Texas Instruments: The World's Most Powerful Pocket Calculator |url=https://books.google.com/books?id=-U8eAQAAMAAJ&q=Texas%20Instruments |journal=[[New Scientist]] |pages=455 |via=[[Google Books]]}}</ref><ref>{{Cite journal |date=October 1978 |title=Patent Victory |url=https://www.worldradiohistory.com/UK/Practical-Electronics/70s/Practical-Electronics-1978-10.pdf |journal=[[Practical Electronics]] |volume=14 |issue=14 |pages=1095 |via=World Radio History}}</ref>}}

The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the [[Sanyo]] ICC-0081 "Mini Calculator", the [[Canon (company)|Canon]] Pocketronic, and the [[Sharp QT-8B]] "micro Compet". The Canon Pocketronic was a development from the "Cal-Tech" project. It had no traditional display; numerical output was on thermal paper tape.

Sharp put in great efforts in size and power reduction and introduced in January 1971 the [[Sharp EL-8]], also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds (721 grams), had a [[vacuum fluorescent display]], rechargeable [[NiCad]] batteries, and initially sold for US$395.

However, [[integrated circuit development]] efforts culminated in early 1971 with the introduction of the first "calculator on a chip", the MK6010 by [[Mostek]],<ref>"Single Chip Calculator Hits the Finish Line", ''Electronics'', February 1, 1971, p. 19.</ref> followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with developments in display technology (such as the [[vacuum fluorescent display]], [[LED]], and [[LCD]]), led within a few years to the cheap pocket calculator available to all.

In 1971, [[Pico Electronics]]<ref>{{cite web |url=http://www.spingal.plus.com/micro |author=James McGonigal |date=September 2010 |orig-year=September 2006 |title=Microprocessor History – Foundations in Glenrothes, Scotland |publisher=Spingal.plus.com |access-date=2011-07-19 |url-status=dead |archive-url=https://web.archive.org/web/20110720142104/http://www.spingal.plus.com/micro/ |archive-date=2011-07-20}}</ref> and [[General Instrument]] also introduced their first collaboration in ICs, a full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant success in the burgeoning handheld calculator market.

The first truly pocket-sized electronic calculator was the [[Busicom]] LE-120A "HANDY", which was marketed early in 1971.<ref>{{cite magazine |title=The one-chip calculator is here, and it's only the beginning |magazine=Electronic Design |date=February 18, 1971 |page=34}}</ref> Made in Japan, this was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the [[Mostek]] MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures {{convert|4.9 x 2.8 x 0.9|in|mm}}.

The first European-made pocket-sized calculator, DB 800<ref>{{cite web |url=http://www.epocalc.net/pages/calc_premieres |title=The first portable calculators |website=epocalc |access-date=30 December 2016 |url-status=dead |archive-url=https://web.archive.org/web/20161028020141/http://www.epocalc.net/pages/calc_premieres |archive-date=28 October 2016}}</ref><ref>{{cite web|url=http://www.jutarnji.hr/40--rodendan-digitrona--u-bujama-je-izraden-prvi-europski-dzepni-kalkulator--te-1971-kostao-je-koliko-i-fico/954368/ |title=U Bujama je izrađen prvi europski džepni kalkulator. Te 1971. koštao je koliko i fićo |trans-title=The first European pocket calculator was made in Buje. In 1971, it cost as much as a son|language=hr|date=20 June 2011 |access-date=30 December 2016|url-status=dead|archive-url=https://web.archive.org/web/20160304003213/http://www.jutarnji.hr/40--rodendan-digitrona--u-bujama-je-izraden-prvi-europski-dzepni-kalkulator--te-1971-kostao-je-koliko-i-fico/954368/|archive-date=4 March 2016}}</ref> was made in May 1971 by [[Digitron (company)|Digitron]] in [[Buje]], [[Croatia]] (former [[Socialist Federal Republic of Yugoslavia|Yugoslavia]]) with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display.

The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed ''The Bowmar Brain''), measuring {{convert|5.2 x 3.0 x 1.5|in|mm}}, came out in the Autumn of 1971, with four functions and an eight-digit red LED display, for {{US$|240}}, while in August 1972 the four-function [[Sinclair Executive]] became the first slimline pocket calculator measuring {{convert|5.4 x 2.2 x 0.35|in|mm}} and weighing {{convert|2.5|oz|g}}. It retailed for around £79 ({{US$|194}} at the time). By the end of the decade, similar calculators were priced less than £5 (${{To USD|5|GBR}}). Following protracted development over the course of two years including a botched partnership with Texas Instruments, [[Eldorado Electrodata]] released five pocket calculators in 1972. One called the Touch Magic was "no bigger than a pack of cigarettes" according to ''Administrative Management''.<ref>{{cite journal |last=Bellotto |first=Sam Jr. |date=August 1972 |title=Calculators: They Just Keep Multiplying |pages=68–73 |url=https://archive.org/details/sim_administrative-management_1972-08_33_8/page/n67 |journal=Administrative Management |volume=33 |issue=8 |publisher=Geyer-McAllister Publications |via=Internet Archive}}</ref>

The first [[Soviet Union]] made pocket-sized calculator, the ''Elektronika B3-04''<ref>{{Cite web |url=http://www.leningrad.su/museum/show_calc.php?n=26 |publisher=Soviet Digital Electronics Museum |title=ELEKTRONIKA B3-04 |work=Коллекция советской цифровой электроники |trans-work=Collection of Soviet digital electronics}}</ref> was developed by the end of 1973 and sold at the start of 1974.

One of the first low-cost calculators was the [[Sinclair Cambridge]], launched in August 1973. It retailed for £29.95 (${{To USD|29.95|GBR}}), or £5 (${{To USD|5|GBR}}) less in kit form, and later models included some scientific functions. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow and less accurate computations of [[transcendental function]]s (maximum three decimal places of accuracy).<ref>{{cite web |url=http://righto.com/sinclair |title=Reversing Sinclair's amazing 1974 calculator hack – half the ROM of the HP-35 |website=Ken Shirriff's blog}} See in particular the section "Limited performance and accuracy". For more coverage of Shirriff's results, see {{cite news |first=Simon |last=Sharwood |date=September 2, 2013 |title=Google chap reverse engineers Sinclair Scientific Calculator |newspaper=The Register |url=https://www.theregister.co.uk/2013/09/02/google_chap_reverse_engineers_sinclair_scientific_calculator/ |archive-url=https://web.archive.org/web/20170823073444/https://www.theregister.co.uk/2013/09/02/google_chap_reverse_engineers_sinclair_scientific_calculator/ |archive-date=August 23, 2017 |url-status=live}}</ref>

===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}}

===Mid-1980s to present===
[[File:Elektronika MK-52.JPG|thumb|The [[Elektronika MK-52]] was a programmable RPN-style calculator that accepted extension modules; it was manufactured in the [[Soviet Union]] from 1985 to 1992]]
The first calculator capable of symbolic computing was the [[HP-28C]], released in 1987. It could, for example, solve quadratic equations symbolically. The first [[graphing calculator]] was the [[Casio fx-7000G]] released in 1985.

The two leading manufacturers, HP and TI, released increasingly feature-laden calculators during the 1980s and 1990s. At the turn of the millennium, the line between a graphing calculator and a [[handheld computer]] was not always clear, as some very advanced calculators such as the [[TI-89]], the [[TI-92 series|Voyage 200]] and [[HP-49G]] could [[derivative|differentiate]] and [[integral|integrate]] [[function (mathematics)|function]]s, solve [[differential equation]]s, run [[word processing]] and [[Personal information manager|PIM]] software, and connect by wire or [[infrared|IR]] to other calculators/computers.

The [[HP 12c]] financial calculator is still produced. It was introduced in 1981 and is still being made with few changes. The HP 12c featured the [[reverse Polish notation]] mode of data entry. In 2003 several new models were released, including an improved version of the HP 12c, the "HP 12c platinum edition" which added more memory, more built-in functions, and the addition of the algebraic mode of data entry.

[[Calculated Industries]] competed with the HP 12c in the mortgage and real estate markets by differentiating the key labeling; changing the "I", "PV", "FV" to easier labeling terms such as "Int", "Term", "Pmt", and not using the [[reverse Polish notation]]. However, CI's more successful calculators involved a line of construction calculators, which evolved and expanded in the 1990s to present. According to Mark Bollman,<ref>{{cite web |author=Mark Bollman |title=Mark->'s Calculator Collection |url=http://mathcs.albion.edu/~mbollman/Calculators.html |website=Mathcs.albion.edu |access-date=2011-07-19 |archive-url=https://web.archive.org/web/20110719135244/http://mathcs.albion.edu/~mbollman/Calculators.html |archive-date=2011-07-19 |url-status=live}}</ref> a mathematics and calculator historian and associate professor of mathematics at Albion College, the "Construction Master is the first in a long and profitable line of CI construction calculators" which carried them through the 1980s, 1990s, and to the present.