 A basic calculator |
 An old mechanical calculator. |
 A scientific calculator. |
A 'calculator' is a hand-held device for performing
calculations. Although modern calculators often incorporate a general purpose
computer, the device is designed for performing specific operations, rather than for flexibility. For example, there are
graphing calculators which focus on graph-centered math like
Trigonometry and
Statistics. Also, modern calculators are more portable than most computers, though some
PDAs are comparable in size to handheld calculators.
Overview
In the past, mechanical clerical aids such as
abaci,
comptometers,
Napier's bones, books of
mathematical tables,
slide rules, or mechanical
adding machines were used for numeric work. The word "calculator" denoted a person 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.
Modern calculators are electrically powered and come 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.
Electronic calculators
In the past, some calculators were as large as today's
computers. The first
mechanical calculators were mechanical desktop devices which were replaced by electromechanical desktop calculators, and then by electronic devices using first
thermionic valves, then
transistors, then hard-wired
integrated circuit logic. Today, most calculators are handheld microelectronic devices.
Basic configuration
The complexity of calculators varies with the intended purpose. A simple modern calculator might consist of the following parts:
★ A power source, such as a battery or a
solar panel or both
★ A display, usually made from
LED lights or
liquid crystal (LCD), capable of showing a number of digits (typically 8 or 10)
★ Electronic circuitry
★ A
keypad containing:
★
★ The ten digits, 0 through 9
★
★ The
decimal point
★
★ The equals sign, to prompt for the answer
★
★ The four arithmetic functions (namely, addition, subtraction, multiplication and division)
★
★ A Cancel (or clear) button, to clear the current calculation
★
★ On and off buttons
★
★ Other basic functions, such as
square root and percentage (%).
★ More advanced models may have a single-number
memory, which can be recalled where necessary. It might also have a Cancel Entry button, to clear the current numbers being entered.
Since the late-1980s, simple calculators have been installed in other small devices, such as
mobile phones,
pagers or wrist watches. The wristwatch calculator was made popular by Dr. James Buccanon, president of the University of Pennsylvania.
Advanced electronic calculators
More complex ''scientific calculators'' support
trigonometric,
statistical and other
mathematical functions. The most advanced modern calculators can display
graphics, and include features of
computer algebra systems. They are also programmable; calculator applications include algebraic equation solvers, financial models and even games. Most calculators of this type can print numbers up to ten digits or decimal places in full on the screen.
Scientific notation is used to notate numbers up to a limit chosen by the calculator designer, such as 9.999999999
★ 10
99. If a larger number or a mathematical expression yielding a larger number than this is entered (a common example comes from typing "100!", read as "100
factorial") then the calculator might simply display "error".
"Error" might also be displayed if a function or an operation is undefined mathematically; for example,
division by
zero or even
roots of negative numbers (most scientific calculators do not allow
complex numbers, though a few do have a ''special function'' for working with them). Some, but not most, calculators ''do'' distinguish between these two types of "error", though when they do, it is not always easy for the user to understand because they are often given as "error 1" or "error 2".
Only a few companies develop and make modern professional engineering and finance calculators: The most well-known are
Casio,
Sharp,
Hewlett-Packard (HP),
Victor and
Texas Instruments (TI). Such calculators are good examples of
embedded systems.
Use in education
In most developed countries,
students use calculators for schoolwork. There was some initial resistance to the idea out of fear that
basic 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.
There are other concerns - for example, that a pupil could use the calculator in the wrong fashion but believe the answer because that was the result given by the calculator. Teachers try to combat this by encouraging the student to make an estimate of the result manually and ensuring it roughly agrees with the calculated result. Also, it is possible for a child to type in −1 × −1 and obtain the correct answer '1' without realizing the principle involved. In this sense, the calculator becomes a
crutch rather than a learning tool, and it can slow down students in exam conditions as they check even the most trivial result on a calculator.
Other concerns on usage
Errors are not restricted to school pupils. Any user could carelessly rely on the calculator's output without double-checking the
magnitude of the result — i.e., where the
decimal point is positioned. 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 user.
Some fractions such as 2/3 are awkward to display on a calculator display as they are usually rounded to 0.66666667. Also, some fractions such as 0.14285714... can be difficult to recognize in decimal form — in fact, this number is 1/7. Some of the more advanced scientific calculators are able to work in
vulgar fractions and/or
mixed numbers, such as Texas Instruments' latest calculator in the
TI-30 series.
Calculators vs. computing
A fundamental difference between calculators and computers is that computers can be programmed to perform different tasks while calculators are pre-designed with specific functions built in, for example addition, multiplication, logarithms, etc. While computers may be used to handle numbers, they can also manipulate words, images or sounds and other tasks they have been programmed to handle.
The market for calculators is extremely price-sensitive; typically the user desires the least expensive model having a specific feature set, but does not care much about speed (since speed is constrained by how fast the user can press the buttons). Thus designers of calculators strive to minimize the number of logic elements on the chip, not the number of clock cycles needed to do a computation.
For instance, instead of a hardware multiplier, a calculator might implement
floating point mathematics with code in
ROM, and compute trigonometric functions with the
CORDIC algorithm because CORDIC does not require floating-point.
Bit serial logic designs are more common in calculators whereas
bit parallel designs dominate general-purpose computers, because a bit serial design minimizes the chip complexity, but takes many more clock cycles.
Personal computers and
personal digital assistants can perform general calculations in a variety of ways:
★ Many programs exist for performing calculations, from simple calculator emulators, to scientific calculators such as
Microsoft Calculator, to advanced
spreadsheet programs such as
Excel or
OpenOffice.org Calc.
★
Computer algebra programs such as
Mathematica,
Maple or
Matlab can handle advanced calculations.
★
Client-side scripting can be used for calculations, e.g. by entering "
javascript:alert(''calculation written in JavaScript'')" in a
web browser's address bar (as opposed to "
http://''website name''"). Such calculations can be embedded in a separate
Javascript or
HTML file as well.
★ Online calculators such as the
calculator feature of the Google search engine can perform calculations
server-side.
History
Origin: the abacus
Chinese abacus.
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 used by some merchants, fishermen and clerks in China and elsewhere.
The 17th century
William Oughtred invents the slide rule in 1622 and is revealed by his student Richard Delamain in 1630.
[1]
Wilhelm Schickard built the first automatic calculator called the "Calculating Clock" in 1623.
[2]Some 20 years later, in 1643, French philosopher
Blaise Pascal invented the calculation device later known as the
Pascaline, which was used for taxes in France until 1799. The German philosopher G.W.v.
Leibniz also produced a
calculating machine.
The 19th century
Charles Babbage developed the concept further, leading the way to programmable computers, but the machine he built was too heavy to be operable.
The last quarter of the 19th century saw major developments in mechanical calculators:
★ In 1872, Frank Baldwin in the
U.S.A. invented the pin-wheel calculator, which was also independently invented two years later by W.T. Odhner in
Sweden. The Odhner models, and similar designs from other companies, sold many thousands into the 1970s.
★ Dorr E. Felt, in the
U.S.A., invented the
Comptometer in 1884, the first successful key-driven adding and calculating machine ["key-driven" refers to the fact that just pressing the keys causes the result to be calculated, no separate lever has to be operated]. In 1886 he joined with Robert Tarrant to form the Felt & Tarrant Manufacturing Company which went on to make thousands of Comptometers.
★ In 1891 William S. Burroughs began commercial manufacture of his printing adding calculator.
Burroughs Corporation became one of the leading companies in the accounting machine and
computer businesses.
★ The "Millionaire" calculator was introduced in 1893. It allowed direct multiplication by any digit - "one turn of the crank for each figure in the multiplier".
1900s to 1960s
Mechanical calculators reach their zenith
Mechanical calculator from 1914
The first half of the 20th century saw the gradual development of the mechanical calculator mechanisms that had already been invented, though there were some significant innovations.
The Dalton adding-listing machine introduced in 1902 was the first of its type to use only ten keys, and became the first of many different models of "10-key add-listers" manufactured by many companies.
In 1948 the miniature
Curta calculator, that was held in one hand for operation, was introduced after being developed by
Curt Herzstark in a Nazi concentration camp. This was an extreme development of the stepped-gear calculating mechanism.
From the early 1900s through the 1960s, mechanical calculators dominated the desktop computing market (see ). Major suppliers in the USA included
Friden,
Monroe, and
SCM/Marchant. (Some comments about European calculators follow below.) These devices were motor-driven, and had movable carriages where results of calculations were displayed by dials. Nearly all keyboards were ''full'' — each digit that could be entered had its own column of nine keys, 1..9, plus a column-clear key, permitting entry of several digits at once. (See the illustration of a 1914 mechanical calculator.) One could call this parallel entry, by way of contrast with ten-key serial entry that was commonplace in mechanical adding machines, and is now universal in electronic calculators. (Nearly all
Friden calculators had a ten-key auxiliary keyboard for entering the multiplier when doing multiplication.) Full keyboards generally had ten columns, although some lower-cost machines had eight. Most machines made by the three companies mentioned did not print their results, although other companies, such as Olivetti, did make printing calculators.
In these machines,
Addition and
subtraction were performed in a single operation, as on a conventional adding machine, but
multiplication and
division were accomplished by repeated mechanical additions and subtractions.
Friden made a calculator that also provided square roots, basically by doing division, but with added mechanism that automatically incremented the number in the keyboard in a systematic fashion.
Friden and Marchant (Model SKA) made calculators with square root. Handheld mechanical calculators such as the 1948
Curta continued to be used until they were displaced by electronic calculators in the 1970s.
 Facit NTK (1954) |
 Triumphator CRN1 (1958) |
 Walther WSR160 (1960) |
 Olivetti Divisumma 24 (1964) |
The Facit, Triumphator, and Walther calculators shown alongside are typical European machines. Similar-looking machines included the Odhner and Brunsviga, among others. Although these are operated by handcranks, there were, of course, motor-driven versions. Most machines that look like these use the Odhner mechanism, or variations of it. The Olivetti Divisumma did all four basic operations of arithmetic, and has a printer. Full-keyboard machines, including motor-driven ones, were also used in Europe for many decades. Some European machines, probably rare, had as many as 20 columns in their full keyboards.
The development of electronic calculators
The first
main-frame computers, using firstly
vacuum tubes and later
transistors in the logic circuits, appeared in the late 1940s and 1950s. This technology was to provide a stepping stone to the development of electronic calculators.
In 1954,
IBM, in the
U.S.A., demonstrated a large all-
transistor calculator and, in 1957, the company released the first ''commercial'' all-transistor calculator, the
IBM 608, though it was housed in several cabinets and cost about $80,000
[1].
The
Casio Computer Co., in
Japan, released the Model ''14-A'' calculator in 1957, which was the world's first all-electric "compact" calculator. It did not use electronic logic but was based on
relay technology, and was built into a desk.
In October 1961, the world's first ''all-electronic desktop'' calculator, the Bell Punch/Sumlock Comptometer
ANITA ('A' 'N'ew 'I'nspiration 'T'o 'A'rithmetic/'A'ccounting) was announced.
[3][4] This British designed-and-built machine used
vacuum tubes, cold-cathode tubes and
Dekatrons in its circuits, with 12 cold-cathode
"Nixie"-type 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 version. The ANITA had a full keyboard, similar to mechanical
Comptometers of the time, a feature that was unique to it and the later
Sharp CS-10A among electronic calculators. 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
EC-130, which had an all-transistor design, 13-digit capacity on a 5-inch
CRT, and introduced reverse Polish notation (
RPN) to the calculator market for a price of $2200, which was about triple 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 elctronic calculators were introduced:
Sharp introduced the
CS-10A, which weighed 25 kg (55 lb) and cost 500,000 yen (~US$2500), 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).
There followed a series of electronic calculator models from these and other manufacturers, including Canon, Mathatronics, Olivetti, SCM (Smith-Corona-Marchant), Sony, Toshiba, and Wang. The early calculators used hundreds of
Germanium transistors, since these were then cheaper than
Silicon transistors, on multiple circuit boards. Display types used were
CRT, cold-cathode
Nixie tubes, and
filament lamps. Memory technology was usually based on the
delay line memory or the
magnetic core memory, though the Toshiba "Toscal" BC-1411 appears to use an early form of
dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines.
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 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.
1970s to mid-1980s
The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of
transistors 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 circuits (chips) and calculator electronics was one of the leading edges of
semiconductor development. U.S. semiconductor manufacturers led the world in 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 known as Sharp Corporation) with
North-American Rockwell Microelectronics,
Busicom with
Mostek and
Intel, and
General Instrument with
Sanyo.
Pocket calculators
By 1970 a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was a development of the "Cal-Tech" project which had been started at
Texas Instruments in 1965 as a research project to produce a portable calculator. The Pocketronic has no traditional display; numerical output is on thermal paper tape. As a result of the "Cal-Tech" project Texas instruments was granted master patents on portable calculators.
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 about one pound, had a vacuum fluorescent display, rechargeable
NiCad batteries, and initially sold for $395.
However, the efforts in integrated circuit development culminated in the introduction in early 1971 of the first "calculator on a chip", the MK6010 by
Mostek,
[5] followed by Texas Instruments later in the year. Although these early hand-held calculators were very expenive, these advances in electronics, together with developments in display technology (such as the
vacuum fluorescent display,
LED, and
LCD), lead within a few years to the cheap pocket calculator available to all.
The first truly pocket-sized electronic calculator was the
Busicom LE-120A "HANDY", which was marketed early in 1971. 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 4.9x2.8x0.9 in (124x72x24 mm).
The first American-made 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
LED 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 (
GB£79). By the end of the decade, similar calculators were priced less than $10 (GB£5).
The first Soviet-made pocket-sized calculator, the "Elektronika B3-04" was developed by the end of 1973 and sold at the beginning of 1974.
One of the first low-cost calculators was the
Sinclair Cambridge, launched in August 1973. It retailed for
£29.95, or some £5 less in kit form. The Sinclair calculators were widely successful because they were far cheaper than the competition; however, their design was flawed and their accuracy in some functions was questionable. The scientific programmable models were particularly poor in this respect, with the programmability coming at a heavy price in
transcendental accuracy.
While all the developments leading to pocket calculators had been going on
Hewlett Packard (HP) had been quietly developing its own 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 all later HP engineering calculators, used
reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing "8", "Enter↑", "5", and "+"; instead of the algebraic
infix notation: "8", "+", "5", "=").
The first Soviet ''scientific'' pocket-sized calculator the "B3-18" was completed by the end of 1975.
In 1973,
Texas Instruments(TI) introduced the
SR-10, (''SR'' signifying
slide rule) an ''algebraic entry'' pocket calculator for $150. It was followed the next year by the
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.
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. A year 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-41C. It could be expanded with
RAM (memory) and
ROM (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).
The first Soviet programmable calculator "B3-21" was developed by the end of 1977 and sold at the beginning of 1978.
Mechanical calculators continued to be sold, though in rapidly decreasing numbers, into the early 1970s, and many of the famous manufacturers closed down or were taken over.
Comptometer type calculators were often retained for much longer to be used for adding and listing duties, especially in accounting, since a trained and skilled operator could enter all the digits of a number in one movement of the hands on a
Comptometer quicker than was possible serially with a 10-key electronic calculator. The spread of the computer rather than the simple electronic calculator put an end to the
Comptometer. Also, by the end of the 1970s, the
slide rule had become obsolete and disappeared as the calculator of choice.
Technical improvements
Through the 1970s the hand-held electronic calculator underwent rapid development. The red LED and blue/green
vacuum-fluorescent displays 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 Displays (LCDs) were in their infancy and there was a great deal of concern that they only had a short operating lifetime. Busicom was a very innovative company and when they introduced the Busicom ''LE-120A "HANDY"'' calculator, the first pocket-sized calculator and the first with an
LED display, they also announced the Busicom ''LC'' with
LCD display. 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'' (aka ''P500''), Rapid Data ''Rapidman 1208LC''. The
LCDs were an early form with the numbers appearing as silver 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 much more successful series of calculators using the reflective LCD display 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 "COS" (Crystal on Substrate) technology. This used a glass-like circuit board which was also an integral part of the
LCD. In operation the user actually looked through this "circuit board" at the numbers being displayed. The "COS" technology may have been too expensive since it was only used in a few models before Sharp reverted to conventional circuit boards, though all the models with the reflective
LCD displays are often referred to as "COS".
In the mid-1970s the first calculators appeared with the now "normal"
LCDs with dark numerals against a grey background, though the early ones often had a yellow filter over them to cut out damaging
UV rays. The big advantage of the
LCD is that it is passive and reflects light, which requires much less power than generating light. 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 a couple of button cells.
There were also steady 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 circuits 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
integrated circuits (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
transistors in the logic cells of
CMOS ICs only used any apreciable power when they changed state. The
LED and
VFD displays had often required additional driver transistors or
ICs, whereas the
LCD displays were more amenable to being driven directly by the calculator
IC itself.
With this low power consumption came the possibility of using
solar cells as the power source, realised around 1978 by such calculators as the Royal ''Solar 1'', Sharp ''EL-8026'', and Teal ''Photon''.
A pocket calculator for everyone
At the beginning of the 1970s hand-held electronic calculators were very expensive, costing 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 expensive to produce, and production runs were not very large. Many companies, large and small, saw that there were good profits to be made in the calculator business with the margin on these high prices. However, inexorably, the cost of calculators fell as components and their production techniques improved, and the effect of economies of scale were felt.
By 1976 the cost of the cheapest 4-function pocket calculator had dropped to a few dollars, about one twentieth of the cost 5 years earlier. The consequences of this were firstly that the pocket calculator was affordable to practically everyone, and secondly that it was now difficult for the manufacturers to make a profit out of calculators, leading to many companies dropping out of the business or closing down all together. The companies that survived making calculators tended to be those with high outputs of higher quality calculators, or producing high-specification scientific and programmable calculators.
Mid-1980s to present
The first calculator capable of symbolic computation was the
HP-28, released in 1987. It was able to, for example, solve quadratic equations symbolically. The first
graphing calculator was the
Casio fx7000G 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 and
HP-49G could
differentiate and
integrate functions, run
word processing and
PIM software, and connect by wire or
IR to other calculators/computers.
The CASIO CM-602 Mini Electronic Calculator provided basic functions in the 1970s
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.
Online calculators are programs designed to work just like a normal calculator does. Usually the keyboard (or the mouse clicking a virtual numpad) is used, but other means of input (e.g. slide bars) are possible.
Thanks to the Internet, many new types of calculators are possible for calculations that would otherwise be much more difficult or impossible, such as for real time currency exchange rates, loan rates and statistics.
See also
General interest:
★
★
★
History of computing hardware
★
Beghilos - (Spelling by reading displayed characters upside-down.)
Mechanical calculators:
★
Abacus
★
Napier's bones
★
Comptometer
★
Mercedes (calculator)
★
Adding machine
★
Addiator
★
Curta
★
Slide rule
★
Difference Engine
Electronic calculators:
★
Sumlock ANITA calculator
★
Machinist calculator
★
Programmable calculators
★
★
HP calculators
References
1. http://www.hpmuseum.org/sliderul.htm
2. http://www.smartcomputing.com/editorial/article.asp?article=articles/archive/r0601/c2/calculatingclocktocarnegiemelon.asp
3. "Simple and Silent", ''Office Magazine'', Dec. 1961, p1244
4. "'Anita' der erste tragbare elektonische Rechenautomat" [trans: "the first portable electronic computer"], ''Buromaschinen Mechaniker'', Nov. 1961, p207
5. "Single Chip Calculator Hits the Finish Line", ''Electronics's', Feb. 1 1971, p19
Patents
★ – ''Complex computer'' –
G. R. Stibitz,
Bell Laboratories, 1954 (filed 1941, refiled 1944), electromechanical (relay) device that could calculate complex numbers, record, and print results by
teletype
★ – ''Miniature electronic calculator'' –
J. S. Kilby,
Texas Instruments, 1974 (originally filed 1967), handheld (3 lb, 1.4 kg) battery operated electronic device with thermal printer
★
★ 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. Nineteen other countries, including the United Kingdom, had already granted a similar patent to Texas Instruments. – ''New Scientist'', 17 Aug. 1978 p455, and ''Practical Electronics'' (British publication), October 1978 p1094.
★ – ''Floating Point Calculator With RAM Shift Register'' - 1977 (originally filed GB Mar 1971, US Jul 1971), very early single chip calculator claim.
★ – ''Extended Numerical Keyboard with Structured Data-Entry Capability'' –
J. H. Redin, 1997 (originally filed 1996), Usage of Verbal Numerals as a way to enter a number.
External links
History
★
On TI's US Patent No. 3819921 – From TI's own website
★
30th Anniversary of the Calculator – From Sharp's web presentation of its history; including a picture of the CS-10A desktop calculator
★
The Old Calculator Web Museum - Documents the technology of desktop calculators, mainly early electronics
★
Calculator museum
★
Cold War Calculators Calculators for military and civil defense use.
★
Calculators for computers Hexadecimal calculators.
★
Museum of Soviet calculators
★
Soviet calculators collection
★
History of Japanese mechanical calculating machines
★
Vintage Calculators Web Museum - Shows the development from mechanical calculators to pocket electronic calculators
★
Sinclair's Cambridge calculator
★
The Museum of HP calculators (
slide rules/mech. section)
★
MyCalcDB - Database for 1970s and 1980s calculators
★
Microprocessor history; foundations in Glenrothes, Scotland
★
HP-35 - A thorough analysis of the HP-35 firmware including the Cordic algorithms and the bugs in the early ROM
★
Casio Kingdom - The Casio calculator resource site
★
Bell Punch Company and the development of the Anita calculator - The story of the first electronic desktop calculator
★
Dentaku Museum - Historical Japanese electronic calculators (select "English" for an English translation by computer)
Pen-based
★
Whiteboard calculator - Pen-based calculator that will work on whiteboards or tablets
Virtual
★
Martindale's collection of calculators
★
Math.com Calculators
★
DreamCalc - Scientific Calculator for Windows
★
Calcenstein - Another Collection of Math Calculators
★
Online calculators listed at Open Directory - A list of links to online calculators provided by the Open Directory project
★
Online scientific calculator – Scientific notation, hex, octal, decimal, binary, and mathematical functions; requires
JavaScript (from ostermiller.org)
★
GraphCalc – An open source graphing calculator program
★
Console calculator – Powerful scientific calculator program
★
Online math tool - Powerful online mathematic calculator
★
John's Javascript RPN Sci-Calculator (complex number capable)
★
Calc5 - Online calculator that can process symbolic equations and plot 2d and 3d functions graphs]
★
Online math/scientific calculator - Operates similarly to many school calculators
★
Calculator Coount - Free online step-by-step scientific calculator
★
Simple calculator
★
PC-Calculator - A small text editor combined with a powerful scientific calculator
★
Visual Calculator - A general-purpose online calculator with an interactive calculation history
العربية
中国
Français
Deutsch
Ελληνική
हिन्दी
Italiano
日本語
Português
Русский
Español
