Calculator

A calculator is a small electronic device used to do calculations. It can handle simple arithmetic or more complex mathematics.

The first electronic calculator was made in the early 1960s. Small pocket calculators became popular in the 1970s after the Intel 4004, the first microprocessor, was created for the Japanese company Busicom. Today, calculators come in many sizes and prices, from tiny, cheap models to larger desktop ones. They became very popular in schools by the late 1970s because they were small, cheap, and easy to use.

There are different types of calculators for different uses. Scientific calculators can do trigonometric and statistical calculations. Graphing calculators can draw graphs of math functions. Basic calculators are very cheap today, but scientific and graphing calculators cost more.

Many operating systems, like old Unix, have calculator programs. Most smartphones, tablets, and other devices have calculator functions built-in. Because so many people carry smartphones, standalone calculators are less common now than they used to be.

Design

Calculators are small electronic devices that help with math. They have a keyboard with buttons for numbers and operations like adding or subtracting. Some calculators have special buttons for big numbers.

Most calculators use liquid-crystal displays to show results. They often show large numbers to make them easier to read. Some can show fractions like 1⁄3 as decimals.

Calculators can also remember numbers. Simple ones remember just one number, while more advanced ones can remember many. They use small batteries, solar power, or electricity to work. Some have a switch to turn them on and off, while others turn off after a while of not being used.

Internal workings

A basic electronic calculator has a few important parts. It needs power, like mains electricity, a battery, or a solar cell. It also has a keypad where you press keys to enter numbers and choose what you want to calculate, such as addition or multiplication. The answers show up on a display panel, which could be a liquid-crystal display or other types of screens.

Inside the calculator, there is a small processor chip that helps it do math problems quickly.

The speed of the processor chip is called its clock rate. For simple calculators, this speed can be slow, but it’s just right for doing basic math.

When you do a simple calculation like 25 + 9, the calculator follows a few steps to get the answer. It takes the numbers you enter, remembers which operation to use, and then adds them together to show the result.

Most small calculators use a special way to store numbers called binary-coded decimal (BCD). This helps make it easier to show the numbers on the screen. For more complicated tasks, the calculator uses special steps called algorithms to get accurate answers.

History

Precursors to the electronic calculator

Main article: Mechanical calculator

See also: Human computer

The first tools for calculations were bones, pebbles, and counting boards, and the abacus, used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism (an astronomical device), the development of computing tools began in the 17th century with inventions like the geometric-military compass, logarithms, Napier bones, and the slide rule.

The Renaissance brought the invention of the mechanical calculator by Wilhelm Schickard in 1623 and later by Blaise Pascal in 1642. Pascal's calculator could add and subtract numbers and could multiply and divide by repeating these actions. There was debate about who should be credited as the inventor of the first calculating machine because of differences in their designs. They were followed by Gottfried Leibniz, who designed a four-operation mechanical calculator but couldn’t create a fully working machine.

The 18th century brought improvements, such as Poleni's first fully functional calculating clock. Luigi Torchi invented the first direct multiplication machine in 1834. Real developments began in the 19th century during the Industrial Revolution. The Arithmometer, invented in 1820 and released in 1851, was the first commercially successful unit.

The familiar push-button user interface was developed in 1902.

In 1921, Edith Clarke invented the "Clarke calculator," a simple graph-based calculator. This helped electrical engineers with calculations for inductance and capacitance in power transmission lines.

The Curta calculator was developed in 1948 and became popular for its portability. By the early 1970s, electronic pocket calculators ended the production of mechanical calculators.

Development of electronic calculators

The first mainframe computers appeared in the 1940s and 1950s. Electronic circuits developed for computers also had uses for electronic calculators.

The Casio Computer Company in Japan released the Model 14-A calculator in 1957, the world's first all-electric compact calculator. It was based on relay technology. The IBM 608 plugboard programmable calculator was IBM's first all-transistor product, released in 1957.

In October 1961, the world's first all-electronic desktop calculator, the British Bell Punch/Sumlock Comptometer ANITA, was announced. The ANITA sold well because it was the only electronic desktop calculator available at the time.

The tube technology of the ANITA was replaced in June 1963 by the U.S.-made Friden EC-130, which had an all-transistor design. In 1964, more all-transistor electronic calculators were introduced, such as the Sharp CS-10A and the IME 84 from Industria Macchine Elettroniche of Italy.

Following this, many manufacturers like Canon, Mathatronics, Olivetti, SCM, Sony, Toshiba, and Wang introduced electronic calculator models. Early calculators used hundreds of germanium transistors. Display types included CRT, cold-cathode Nixie tubes, and filament lamps.

Bulgaria's ELKA 6521, introduced in 1965, was the first calculator in the world to include the square root function. Later that year, the ELKA 22 and ELKA 25 were released, and the first pocket model, the ELKA 101, came out in 1974.

Programmable calculators

Main article: Programmable calculator

The first desktop programmable calculators were produced in the mid-1960s. The Programma 101 saw wider distribution and had the feature of storing programs on magnetic cards.

Another early programmable desktop calculator was the Casio (AL-1000) from 1967.

The Monroe Epic programmable calculator came on the market in 1967.

The first Soviet programmable desktop calculator ISKRA 123 was released at the start of the 1970s.

1970s to mid-1980s

Electronic calculators of the mid-1960s were large and heavy desktop machines. Efforts focused on reducing the number of integrated circuits (chips) needed for a calculator.

Pocket calculators

"Pocket calculator" redirects here. For the song, see Computer World.

Released in 1947, the first pocket calculator that could perform the four basic arithmetic functions was the Curta, a mechanical device operated by a crank.

By 1970, calculators could be made using just a few chips of low power consumption, allowing portable models powered by rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech, led by Jack Kilby at Texas Instruments.

The first commercially produced portable calculators appeared in Japan in 1970 and were soon marketed worldwide. These included the Sanyo ICC-0081 "Mini Calculator," the Canon Pocketronic, and the Sharp QT-8B "micro Compet."

Sharp introduced the Sharp EL-8 in January 1971.

Integrated circuit development led to the first "calculator on a chip," the MK6010 by Mostek, followed by Texas Instruments later that year.

The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY," marketed in early 1971.

The first European-made pocket-sized calculator, DB 800, was made in May 1971 by Digitron in Buje, Croatia.

The first American-made pocket-sized calculator, the Bowmar 901B, came out in autumn 1971.

The first Soviet-made pocket-sized calculator, the Elektronika B3-04, was developed at 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.

Scientific pocket calculators

Main article: Scientific calculator

Meanwhile, Hewlett-Packard had been developing a pocket calculator. Launched in early 1972, it was the first pocket calculator with scientific functions that could replace a slide rule.

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

In 1973, Texas Instruments introduced the SR-10, an algebraic entry pocket calculator using scientific notation for $150. It was followed by the SR-11 with a key for entering pi (π), and then the SR-50, which added log and trig functions. In 1977, the mass-marketed TI-30 line was introduced and is still produced.

In 1978, Calculated Industries arose, focusing on specialized markets.

Adler 81S pocket calculator with [vacuum fluorescent display](/wiki/Vacuum_fluorescent_display) (VFD) from the mid-1970s.

The Casio CM-602 Mini electronic calculator provided basic functions in the 1970s.

The 1972 [Sinclair Executive](/wiki/Sinclair_Executive) pocket calculator.

The [HP-35](/wiki/HP-35), the world's first scientific pocket calculator by Hewlett Packard (1972).

Canon Pocketronic calculator prints output using paper tape (1971).

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.

The first Soviet pocket battery-powered programmable calculator, Elektronika B3-21, was developed at the end of 1976 and released at the start of 1977. The successor, the Elektronika B3-34, defined a new command set used in later Soviet calculators.

This series of calculators was noted for many undocumented features.

A similar hacker culture in the US revolved around the HP-41.

Technical improvements

Through the 1970s, handheld electronic calculators underwent rapid development.

Improvements to the electronics inside calculators also occurred. Logic functions were squeezed into the first "calculator on a chip" integrated circuits (ICs) in 1971

The power consumption of ICs was reduced, especially with the introduction of CMOS technology.

With low power consumption came the possibility of using solar cells as a power source, realized around 1978 by calculators like the Royal Solar 1, Sharp EL-8026, and Teal Photon.

The interior of a Casio fx-20 scientific calculator from the mid-1970s, using a VFD. 

The processor chip (integrated circuit package) inside a 1980s Sharp pocket calculator, marked SC6762 1•H. 

The interior of a newer (c. 2000) pocket calculator. It uses a button battery in combination with a solar cell. 

Mass-market phase

At the start of the 1970s, handheld electronic calculators were very costly, making them a luxury item. The high price was due to their construction requiring many mechanical and electronic components. However, the cost of calculators fell as components and production methods improved.

By 1976, the cost of the cheapest four-function pocket calculator had dropped to a few dollars. This made pocket calculators affordable.

Mid-1980s to present

The first calculator capable of symbolic computing was the HP-28C, released in 1987.

The leading manufacturers, HP and TI, released increasingly feature-laden calculators during the 1980s and 1990s.

The HP 12c financial calculator is still produced. Introduced in 1981, it is still made with few changes.

Calculated Industries competed with the HP 12c in the mortgage and real estate markets. However, CI's more successful calculators involved a line of construction calculators, which evolved and expanded in the 1990s to present.

Use in education

Students in many countries use calculators for schoolwork. Some people worried that using calculators might make it harder to do simple math in your head. Because of this, some schools only allow students to use calculators after they have learned certain skills. Others focus more on teaching how to estimate numbers and solve problems.

Research shows that if teachers don’t guide students well on how to use calculators, it might limit the kinds of math problems students can solve. Some believe that using calculators too much can make it harder to understand more advanced math topics. In 2011, a leader in the UK expressed concern that children might rely too much on calculators, so plans were made to review how calculators are used in school. In the United States, many math teachers and school boards support using calculators from early grades all the way through high school.

Sometimes, calculators are allowed in exams at school or college. In the UK, there are rules about which calculators can be used in exams to make sure everyone plays fair. Some calculators have a special setting called “exam mode” that makes them follow these rules.

Personal computers

Many personal computers have a special program that looks and works like a calculator. These programs use the screen to show a calculator that you can use. Examples include the Windows Calculator, Apple's Calculator, and KDE's KCalc. Most personal data assistants and smartphones also have a similar feature.

Calculators compared to computers

The main difference between a calculator and a computer is that a computer can do many different tasks, while calculators are made for specific jobs like addition, multiplication, and logarithms. Some special calculators, called programmable calculators, can also do more things, sometimes using programming languages like RPL or TI-BASIC.

Calculators often use simpler ways to do math, like using code stored in memory. They work step by step, which makes them easier to make but slower than most computers. Some advanced calculators use the same types of chips that are found in computers.

Software calculators

See also: Comparison of software calculators and Software calculator