calculator

an expert at calculation (or at operating calculating machines) a small machine that is used for mathematical calculations

A calculator is a device for performing numerical calculations. The type is considered distinct from both a calculating machine and a computer in that the calculator is a special-purpose device that may not qualify as a Turing machine. Although modern calculators often incorporate a general purpose computer, the device as a whole is designed for ease of use to perform specific operations, rather than for flexibility.The complexity of calculators varies with the intended purpose. A simple one with only four functions (addition, subtraction, multiplication and Division (mathematics)division and perhaps a single-number Computer storagememory) may be useful for everyday activities such as shopping or checking a bill. More complex ones may include complex mathematical functions suitable to engineering or accounting as well as a substantial memory and the ability to execute moderately complex Computer programprograms. Since the late-1980's, it has become common to incorporate simple calculators in other small devices, such as mobile phones, pagers or watchwrist watches.In most developed countries, students use calculators for schoolwork. There was some initial resistance to the idea out of fear that Elementary arithmeticbasic arithmetic skills would suffer. There remains disagreement about the importance of the ability to perform calculations by hand or "in the head", with some curricula restricting calculator use until a certain level of proficiency has been obtained, while others concentrate more on teaching estimation techniques and problem-solving.

Overview - Modern calculators are electrically powered, most often by battery, and are made by numerous manufacturers, in countless shapes and sizes varying from cheap, give-away, credit-card sized models to more sturdy adding machine-like models with built-in printers. Only a very few companies develop and make modern professional engineering and finance calculators: The most well-known are Casio, Sharp CorporationSharp, Hewlett-PackardHewlett-Packard (HP) and Texas InstrumentsTexas Instruments (TI). Such calculators are good examples of embedded systems. They are also often complex enough to be programmed; calculator applications include algebraic equation solvers, financial models and even games.In the near past, mechanical and clerical aids such as abacusabacuses, comptometers, Napier's bones, books of mathematical tables, slide rules, adding machines, were used for serious numeric work, and the word "calculator" denoted a person (most often male) who did such work for a living using such aids as well as pen and paper. This semi-manual process of calculation was tedious and error-prone.

Electronic calculators - Today most calculators are handheld microelectronic devices, but in the past some calculators were as large as today's computers. The first mechanical calculators were mechanical desktop devices, which were soon replaced by electromechanical desktop calculators, and then by electronic devices using first thermionic valves, then transistors, then hard-wired integrated circuit logic.A pocket calculator is a small battery-powered or solar powered electronic digital computer made possible by integrated circuit and semiconductor technology. Typically they are limited to an 8–10 digit single-number display and a few basic functions of arithmetic, but some modern calculators have more of the features of a general-purpose computer. Pocket calculators rendered the slide rule obsolete.Calculators vary in their capabilities. Some are limited to only basic arithmetic; others support trigonometric functiontrigonometric, statisticsstatistical and other list of functionsmathematical functions. The most advanced modern calculators are programmable, can display graphics, and include features of computer algebra systems.

Personal computing - Personal computers and personal digital assistants can perform general calculations in a variety of ways:

computers often have a separate calculator program, varying from one that just emulates a simple calculator, such as Microsoft Calculator, to advanced spreadsheet programs such as Microsoft ExcelExcel or OpenOffice.org Calc

for more advanced calculations one can use a computer algebra program, such as Mathematica, Maple computer algebra systemMaple or Matlab.

browsers can perform calculations using client-side scripting, e.g. using Client-side JavaScript by entering !"javascript:alert(12*13)& quot;? in the address bar (the answer 156 appears in a separate alert window) or "document.write (12*13)" in a HTML file, preceded with "".an interpreter or compiler for a general programming language can be used

calculations can also be performed server-side, e.g. with the !List_of_Google_services_and_to ols#Calculatorcalculator feature of the Google search engine

History -

Origin: The Abacus - mainAbacus The first calculators were abacuses, and were often constructed as a wooden frame with beads sliding on wires. Abacuses were in use centuries before the adoption of the written Arabic numerals system and are still widely used by merchants and clerks in China and elsewhere.

The 17th century - Wilhelm Schickard built the first automatic calculator called the "Calculating Clock" in 1623. Some 20 years later, in 1645, French philosopher Blaise Pascal invented the calculation device later known as Pascal's calculator, which was used for taxes in France until 1799.

1930s to 1960s - From approximately the 1930s through the 1960s, mechanical calculators were often used (see ''Mechanical Calculator'' under History of computing hardware). These desktop devices were motor-driven and had multiple columns of keys for each digit. Addition and subtraction were performed in a single operation, as on a conventional adding machine, but multiplication and division (mathematics)division were accomplished by repeated mechanical additions and subtractions. Handheld mechanical calculators such as the Curta continued to be used until they were displaced by electronic calculators in the 1970s.In 1954, IBM demonstrated a large all-transistor calculator and, in 1957, they released the first ''commercial'' all-transistor calculator (the IBM 608). In October 1961, the world's first ''all-electronic desktop'' calculator, the Bell Punch/Sumlock Comptometer ANITA Mk.VII was released. This British designed-and-built machine used vacuum tubes in its circuits and cold-cathode nixie tubes for its display. It was superseded, technologically, in 1964 when Sharp CorporationSharp introduced the CS-10A—the world's first ''all-transistor'' ''desktop'' calculator—which weighed 25 kg (55 lb) and cost 500,000 yen (~US$2500). The first ''handheld'' electronic calculators went on sale in 1970 with models from Japanese manufacturers Sharp and Canon Inc.Canon weighing around 770 g (1.7 lb).

1970s to mid-1980s - In the early 1970s, the ''Monroe EPIC'' programmable calculator came on the market. A large desk-top unit, with an attached floor-standing logic tower, it was capable of being 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 pocket-sized calculator, the Bowmar 901B (popularly referred to as ''The Bowmar Brain''), measuring 5.2×3.0×1.5 in (131×77×37 mm), came out in the fall of 1971, with four functions and an eight-digit red light-emitting diodeLED display, for $240, while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4×2.2×0.35 in (138×56×9 mm) and weighing 2.5 oz (70g). It retailed for around $150 (Pound SterlingGB£79). By the end of the decade, similar calculators were priced less than $10 (GB£5).The first pocket calculator with ''scientific'' functions, i.e. the first slide rule-replacing model, was the 1972 HP-35 from Hewlett PackardHewlett Packard (HP); it, along with all later HP engineering calculators, used reverse Polish notation (RPN) (where a calculation like "6 – 2" is performed by pressing "6", "Enter↑", "2", and "–"; instead of algebraically: "6", "–", "2", "=").In 1973, Texas InstrumentsTexas Instruments (TI) introduced the SL-10, (''SL'' signifying slide rule) a hand-held ''algebraic notation'' calculator, which was later followed by the SL-11 and eventually the TI-30.The first ''programmable'' hand-held 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. A year later the HP-25C introduced ''continuous memory'', i.e. programs and data were retained in memory during power-off. In 1979, HP released the first ''alphanumeric'', programmable, ''expandable'' calculator, the HP-41HP-41C. It could be expanded with random access memoryRAM (memory) and read-only memoryROM (software) modules, as well as peripherals like bar code readers, microcassette and floppy disk drives, paper-roll thermal printers, and miscellaneous communication interfaces (RS-232, HP-IL, HP-IB).

Mid-1980s to present - graphing calculator from Texas Instruments.]] on a TI-89 seriesTI-89 calculator.]]The two leading manufacturers, HP and TI, released steadily more feature-laden calculators during the 1980s and 90s. At the turn of the millennium, the line between a graphing calculator and a PDA/ handheld computer was not always clear (forgetting the keyboard for the sake of the argument), as some very advanced calculators such as the TI-89 and HP-49G could derivativedifferentiate and integrationintegrate function (mathematics)functions, run word processing and Personal information managerPIM software, and connect by wire or infraredIR to other calculators/computers.In March 2002, HP announced that the company would no longer produce calculators, which was hard to fathom for some fans of the company's products; the HP-48 range in particular had an extremely loyal customer base. Nevertheless, HP restarted their production of calculators in late 2003. The new models, however, reportedly didn't have the mechanical quality and sober design HP's earlier calculators were famous for (instead featuring the more "youthful" look and feel of contemporary competing designs from TI).The business calculator HP-12C is still produced. It was introduced in 1981 and is still being made with nearly no changes. In 2003 several new models were released, including an improved version of the HP-12C, the "HP-12C platinum edition".

Drawbacks -

Built-in inaccuracy commonly due to arithmetic underflow is a drawback occurring in many ordinary digital calculators. To obtain an example of this potential problem, the following exercise may be performed: enter the number ''one'', divide by ''three'', to reach ''0.333'' (recurring, i.e. followed by a theoretically infinite number of 3s), and then multiply by ''three'' to get back to ''one''. On some calculators this operation will not work correctly, in that the result is given as ''0.999'' (recurring)—roughly speaking, this anomaly happens because the calculator works with only a finite number of decimals.

Another kind of "drawback" resulting from the use, rather than the construction, of calculators, is the tendency of users to carelessly rely on the calculator's output without double-checking the orders of magnitudemagnitude (in practice, the placement of the decimal separator) of the result. This problem was all but nonexistent in the era of slide rules and pencil-and-paper calculations, when the task of establishing the magnitudes of results had to be done by the (sufficiently meticulous) user.

Trivia -

The word "calculator" is occasionally used as a pejorative term to describe an inadequately capable general-purpose microcomputer. The synonym of this meaning is "wikt:bitty boxbitty box", as discussed in the Jargon file.

A curious episode of the mid 1970s involved the Melcor 635, a scientific calculator with a computer bugbug in its trigonometrytrigonometric functions. Because the CORDIC algorithms used in most calculators cannot compute the inverse trigonometric functions of 0 (number)zero, these need to be hardcoded — and some engineer at Melcor got it wrong. For any input other than exactly zero, even for instance 1.0E-99, the calculator worked correctly; the user simply had to remember not to compute the trigonometric function#inverse functionsarc-cosine of zero. The company discovered this after making 50,000 calculators. The upshot was an advertisement in ''Scientific American'' headlined 'Somebody Goofed', offering these calculators for sale at half-price.

As many schoolchildren and students know, some words and simple phrases can be written using an ordinary seven-segment display calculator; this involves entering calculator spellingcertain numbers and then viewing the resulting words by turning the calculator display upside-down.

See also - General interest:

:Category:Calculators

History of computing hardwareMechanical calculators:

Abacus

Napier's bones

Comptometer

Mercedes (calculator)

Adding machine

Addiator

Curta calculatorCurtaElectronic calculators:

List of calculators

Patents -

US patent2668661 – ''Complex computer'' – George StibitzG. R. Stibitz (electromechanic device that would calculate, record, and print results)

US patent3819921 – ''Miniature electronic calculator'' – Jack KilbyJ. S. Kilby (TI electromechanic device)

External links -

ti.com - On TI's US Patent No. 3819921 – From TI's own website

sharp-world.com - 30th Anniversary of the Calculator – From Sharp's web presentation of its history; including a picture of the CS-10A desktop calculator

maths.hscripts.com - Online Calculators and Converters

web.peoriadesignweb.com - Online Calculator Software

satsig.net - Online deep space SETI range calculator

ostermiller.org - JavaScript Scientific Calculator – Scientific notation, hex, octal, decimal, binary, and math functions; requires JavaScript (from ostermiller.org)

oldcalculatormuseum.com - The Old Calculator Web Museum

calculators.de - Calculator Museum

taswegian.com - Museum of Soviet Calculators

rk86.com - Soviet Calculators Collection

vintagecalculators.com - Vintage Calculators

lendingok.com - various calculators

cut-the-knot.org - Broken Calculator

graphcalc.com - GraphCalc – an Open Source graphing calculator program

binarythings.com - HiDigit scientific calculator

hpmuseum.org - The Museum of HP Calculators (hpmuseum.org - slide rules/mech. section)

hydrix.com - HP Calculator Wiki

? typeonline.co.uk - Number pad typing tutorial

casiocalc.org - International Casio Calculator Community

graph100.com - French Casio Calculator Community Category:Calculators!*CalculatorCategory:Mathematic al? toolsCategory:Office !equipmentda:Lommeregnerde:Tasc henrechneres:Calculadoraeo:Kal kulilofr:Calculatricehe:מ ;חשבו& #1503;nl:Rekenmachineja:༙ 1;卓pl:Kalkulatorpt:Calc uladoraru:Кал ;ькул& #1103;торsl: računalosr:Дигитро нfi:Laskinsv:Miniräknareth:� ��ครื่องคิด� ��ลขzh:电子计算器

Satellite Internet for all
Details of satellite communications beam coverage patterns providing broadband VSAT services worldwide. Miscellaneous tools include link budget calculator, dish pointing calculator (good for satellite television) and worldwide latitude longitude finder.
http://www.satsig.net/

Ezy Loan Calculator
Ezy Loan Calculator is a very user friendly loan amortization software. It has the following features extra payments, skipped payments, late payments, lump sum payments, graphs, interest rate change, country compounding, save and retrieves data, Exports data to HTML or CSV file, preview & print data, free 30 days trial download, free version upgrades, free product support.
http://www.ezyloancalculator.com/

Signal DIsplay Systems
Displays, Communications, Encryption, Electronics
http://www.signaldisplay.com/

Handheld Computer Software
Software products for handheld computers.
http://www.jayts.cx/

Bali Online
Travel portal including planner, photos, and information.
http://www.indo.com/

Calculator.com
Online calculators for a variety of conversions and calculations.
http://www.calculator.com/

Calculator.org
Calculator resources including free download of scientific engineering, statistical, and financial calculators.
http://www.calculator.org/