Texas Instruments Introduces the Pocket Calculator Summary

  • Last updated on November 10, 2022

Texas Instruments’ production of a miniature electronic calculator—portable, reliable, and handheld—revolutionized computations by scientists, mathematicians, engineers, and the general public, ushering in the age of the low-cost consumer electronics.

Summary of Event

In the earliest accounts of civilizations that developed number systems to record mathematical calculations, evidence has been found of efforts to fashion a device that would permit people to perform these calculations with reduced effort and increased accuracy. The ancient Babylonians are regarded as the inventors of the first abacus (or counting board, from the Greek abakos, meaning “board” or “tablet”). It was originally little more than a row of shallow grooves with pebbles or bone fragments as counters, but it enabled people five thousand years ago to calculate much more efficiently than the often awkward and complex number systems. Texas Instruments Calculators Pocket calculators Datamath (calculator) [kw]Texas Instruments Introduces the Pocket Calculator (Sept. 21, 1972) [kw]Pocket Calculator, Texas Instruments Introduces the (Sept. 21, 1972) [kw]Calculator, Texas Instruments Introduces the Pocket (Sept. 21, 1972) Texas Instruments Calculators Pocket calculators Datamath (calculator) [g]North America;Sept. 21, 1972: Texas Instruments Introduces the Pocket Calculator[00870] [g]United States;Sept. 21, 1972: Texas Instruments Introduces the Pocket Calculator[00870] [c]Science and technology;Sept. 21, 1972: Texas Instruments Introduces the Pocket Calculator[00870] [c]Mathematics;Sept. 21, 1972: Texas Instruments Introduces the Pocket Calculator[00870] [c]Computers and computer science;Sept. 21, 1972: Texas Instruments Introduces the Pocket Calculator[00870] Kilby, Jack St. Clair Merryman, Jerry D. Van Tassel, James

The introduction of Hindu-Arab numerals into Europe during the eighth and ninth centuries suggested that further advances were possible, but the next step in mechanical calculation did not occur until John Napier, a Scottish baron, placed figures on rods in the early seventeenth century. This concept led to the first slide rule, a pair of circles numbered by William Oughtred of Cambridge, which made it possible to perform rough but rapid multiplication and division. Oughtred’s invention in 1623 was paralleled by the work of a German professor, Wilhelm Schickard, who built a “calculating clock” in the same year, but because the record of his work was lost until 1935, the French mathematician Blaise Pascal generally was thought to have built the first mechanical calculator, the “Pascaline,” in 1645.

Other versions of mechanical calculators were built in subsequent centuries, but none was rapid or compact enough to be useful beyond specific laboratory or mercantile situations. The dream of such a machine continued to fascinate scientists and mathematicians, but the crucial development that made it possible did not occur until the middle of the twentieth century, when Jack St. Clair Kilby of Texas Instruments invented the silicon microchip (or integrated circuit) Integrated circuits in 1958. The chip is a sliver of germanium hardly more than a centimeter long that could do the work of the much larger transistor. Kilby had been familiar with the transistor (invented by Bell Laboratories Bell Telephone Laboratories in 1947) from his work at Centralab, Inc., a radio and television parts manufacturer in Milwaukee, Wisconsin. In joining Texas Instruments, a pioneering company that had manufactured the first silicon transistor in 1954, he had the opportunity to pursue his ideas about putting all the individual components of a circuit on an integrated, single, compact base.

Patrick Haggerty, then president of Texas Instruments, had written in 1964 that “integrated electronics” would “remove limitations” that determined the size of instruments, and he recognized that Kilby’s invention of the microchip made the creation of a portable, handheld calculator a practical possibility. Microelectronics He challenged Kilby to put together a team to design a calculator that would be as powerful as the large, electromechanical models in use at the time but small enough to fit into a coat pocket. Working with Jerry D. Merryman and James Van Tassel, Kilby began to work on the project in October, 1965.

Five elements had to be designed: the logic designs, which enabled the machine to perform the actual calculations; the outer keyboard, which signaled the assigned problem to the functioning circuit; the power supply, which drove the entire operation; the readout, which provided the answer to the problem; and the outer enclosure, which contained the works. All of these required specific creative solutions to what were basically new problems. Kilby later recalled that once a particular size for the unit (something that could be easily held in the hand) was determined, project manager Merryman was able to develop the initial logic designs in three days. Merryman was able to accomplish everything required without exceeding the relatively meager power supply that would be available from the low-output batteries necessary to ensure portability.

A early pocket calculator.


Van Tassel contributed his experience with semiconductor components to solve the problems of packaging the integrated circuit. Most available integrated circuits in use had fourteen or sixteen leads, and Van Tassel was obliged to work with 120 leads, the minimum required to handle the basic functions Kilby believed were crucial for success. Van Tassel had to determine the coefficient of expansion of the separate chips and to devise a way to make reliable contacts among the chips so that the integrated circuit was attached securely at all points. In addition, the chips that were available were inconsistent in quality and had to be individually probed. Those found to satisfy the standards had to be individually matched for common workable areas. The display to record the results required a thermal printer that would work on the low power source, and it had to include a microencapsulated ink source that was available when the paper readout was pressed against a heated digit. After the result was recorded in this manner, the paper had to be advanced for the next calculation. Kilby, Merryman, and Van Tassel filed for a patent on their work in 1967.

Although this relatively small, working prototype of the minicalculator made the transistor-operated design of the much larger desk calculator obsolete, the cost of setting up new production lines and the necessities of developing a market made it impractical to begin production immediately. Instead, Texas Instruments and Canon, Inc., of Tokyo formed a joint venture, which led to the introduction of the Canon Pocketonic Printing Calculator in Japan in April, 1970, and in the United States that fall. Built entirely of Texas Instruments parts, this four-function machine with three metal oxide semiconductor (MOS) circuits was similar to the prototype designed in 1967, but it weighed about one-third less because a plastic case replaced the almost solid aluminum case in the original. It used nickel-cadmium batteries, which were lighter in weight and reliable enough to replace the silver-zinc batteries in the original. The calculator was priced at four hundred dollars, weighed 740 grams, and measured 101 millimeters wide by 208 millimeters long by 49 millimeters high. It could perform twelve-digit calculations and worked up to four decimal places.

On September 21, 1972, Texas Instruments officially released the Datamath, its first commercial handheld calculator using a single MOS chip, to the retail market. It weighed 340 grams and measured 75 by 137 by 42 millimeters. The Datamath was priced at $120 and included a full-floating decimal point unit, so that the decimal could appear anywhere among the numbers on its eight-digit light-emitting diode (LED) display. It came with a rechargeable battery that could also be connected to a standard AC outlet. It used algebraic forms for its four basic functions—addition, subtraction, multiplication, and division—and enabled the user to press the keys as the problem progressed. At the heart of the calculator, the integrated semiconductor circuit (the silicon chip) contained all the necessary electronics for performing all functions, and it had ten digit keys, seven function keys, and a decimal location key. When the battery needed charging, all eight decimal points were activated.

Beyond its standard computation capability, the Datamath would turn off the display except for the character in the first position after fifteen seconds if the action was interrupted, thereby conserving power until another keyboard entry was made. One of its more sophisticated features was a constant/chain switch to offer a selection between a function permitting multiplication or division by a constant or making available the last calculation for use in further calculation in a chain of entries. This limited memory element anticipated the evolution of the calculator/computer combination with much more extensive memory storage. The Datamath had a total of 111 parts, 43 of which were electronic.


In recognition of the significance of the work by the Texas Instruments team of Kilby, Merryman, and Van Tassel, in 1975 the Smithsonian Institution Smithsonian Institution accepted the world’s first miniature electronic calculator for its permanent collection, noting that it was the forerunner of more than one hundred million pocket calculators then in use. Decades later, many units selling for less than ten dollars could do much more than the CS-104 made by Sharp Corporation of Tokyo in 1964, a fifty-five-pound model that sold for twenty-five hundred dollars. Kilby’s dream had been realized.

Beyond the immediate practicality of the device, however, this invention, which heralded the age of the low-cost consumer-portable calculator and was instrumental in launching the still-growing electronic calculator industry, also revolutionized the manner in which the human race related to the world of numbers. Instead of gaining familiarity with figures by painstakingly adding long columns of numbers, children were now able to combine the basic principles of addition and subtraction with the instant responses to problems that simple calculators provided. Thus a new generation of students may have become less skilled with numbers, but they were able to overcome the fear of numbers that held many people back from even a preliminary understanding of mathematics. Similarly, while classes in many fields of engineering and industrial education were occupied previously by the laborious tasks of working out routine problems through numerous steps, the calculator permitted students to race through multistepped problems—the classic extensive number crunching required in many graduate laboratory projects in particular—and permitted more classroom time for more creative and analytic thinking.

Prior to 1970, most calculating machines were of such dimensions that professional mathematicians and engineers were tied to their desks or carried slide rules when they were compelled to work in the field. By 1975, Keuffel & Esser, the largest slide rule manufacturer in the world, was producing its last model, and mechanical engineers found that problems that had previously taken a week could now be solved in an hour. As Irene Kim, a news editor for Mechanical Engineering magazine, stated, four major aspects of engineering could be handled by calculators: “running programs on calculators; using preprogrammed calculators as control devices; using calculators to help write programs on a computer; and basic calculating which may or may not include programming.”

The portability of the handheld calculator made it ideal for use in remote locations, such as those a petroleum engineer might have to explore, while its rapidity and reliability made it an indispensable instrument for construction engineers, architects, and real estate agents, who could figure the volume of a room and other building dimensions almost instantly and then produce cost estimates by referring to previous programs almost on the spot. Beyond all the uses that the mechanical engineering professions required, the nonprofessional segment of the population—depending on remote controls to operate home entertainment devices of all kinds, mobile phones, and more—began to develop new habits of communication dependent on the pioneering work done at Texas Instruments. Texas Instruments Calculators Pocket calculators Datamath (calculator)

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Augarten, Stan. Bit by Bit: An Illustrated History of Computers. New York: Ticknor & Fields, 1984. Lucidly written and well-illustrated work contains diagrams and color photographs as well as black-and-white photographs and portraits. Includes an excellent history of calculating machines and a chapter on Kilby’s work. Excellent notes and bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Braun, Ernest, and Stuart Macdonald. Revolution in Miniature: The History and Impact of Semiconductor Electronics. New York: Cambridge University Press, 1978. Thorough and clearly written volume covers the entire field of semiconductor electronics, explaining the place of the calculator in terms of historic developments. Most of the material is aimed at readers with some knowledge of scientific terminology.
  • citation-type="booksimple"

    xlink:type="simple">Kim, Irene. “Functions at the Fingertips.” Mechanical Engineering 112 (January, 1990). A very informative and accessible essay about the work of Kilby, Merryman, and Van Tassel, combined with a survey of the multiple uses of handheld calculators by mechanical engineers in the last decade of the twentieth century.
  • citation-type="booksimple"

    xlink:type="simple">Pirtle, Caleb, III. Engineering the World: Stories from the First Seventy-Five Years of Texas Instruments. Dallas: Southern Methodist University Press, 2005. Nicely illustrated, anecdotal history of the revolutionary company.
  • citation-type="booksimple"

    xlink:type="simple">Reid, T. R. The Chip: How Two Americans Invented the Microchip and Launched a Revolution. Rev. ed. New York: Random House, 2001. A thorough, detailed history of the invention and development of the microchip, combining history and technology on both the level of the general reader and the scientist.

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