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The History of Pocket Electronic Calculators

Copyright 1996 by Guy Ball and Bruce Flamm

1960's Sowing the seeds of the calculator revolution

Early 1960's -- Mechanical calculators, slide rules, or paper and pencil are the world's main methods of calculation. As was true in the 1940's and 1950's, early 1960's calculators are complicated motor-assisted mechanical adding machines with no other electronic parts. They are called calculators rather than adding machines because complex gear systems allow them to perform multiplication and division by repetitive addition or subtraction. One mechanical model made by Friden is actually able to use gears and levers to extract square roots.

1963 -- Bell Punch Co. LTD and Sumlock-Comptometer LTD of England introduce the "Anita" which is claimed to be the world's first fully electronic desk-top calculator. The machine weighs 33 pounds and uses dozens of vacuum tubes (called valves in England) along with hundreds of other discrete components. Although the Anita is as large as many mechanical models, it is a major breakthough since it is silent (no moving parts) and very fast. In the USA, the Friden 130 was released at about the same time. It used a CRT (cathode ray tube ) television tube - type of display and was also one of the first fully electronic calculators in the world.

1964 -- In March, Japan's Sony Corporation claims to perfect the world's first all-transistorized (no vacuum tube) desk-top electronic calculator. Quite a hit when it was displayed at the 1964 New York World's Fair, their model MD-5 was capable of 8-digit computations and used magnetic (transistorized) switching with a Nixie tube display. Beginning from this R & D development, Sony later improved functional operations and operating systems through several later models before finally deciding several years later that their SOBAX ("solid state abacus") line of desk-top calculators was far less profitable than anticipated. Before exiting from the calculator market, however, Sony forever left its mark on technological history by not only being "first" but also by development of SOBAX features used in virtually all later calculators, i.e., disappearing zeros (to left of displayed digits), floating decimal, the "rounding off" feature, percentage computations, and reciprocals.

1964 -- Victor Business Machines contracts with General Micro-electronics (USA) to develop a metal-oxide semiconductor (MOS), integrated circuit (IC) based desk-top calculator. GMe was never able to resolve enough of their process manufacturing problems to deliver the ICs. (Victor did briefly sell some pocket and portable calculators during the early 1970's, but apparently most were made for them by other companies.)

1964-67 -- The first large electronic desk-top calculators begin to replace electro-mechanical machines. Those models, based on the newest electronic technology, use thousands of transistors, cost thousands of dollars, and weighed 30-60 pounds. Sharp's Compet CS-10A and Canon's Canola 130 are two early electronic calculators among the offerings from over thirty manufacturers in an intense international competition to offer the most advanced product. (In reference to the Sony information above, Sharp also claims to have the first all-transistorized machine.) Meanwhile, some innovators begin to dream about using this technology to build an electronic calculator that would be small enough to hold in your hand.

1965 -- Texas Instruments (USA) begins work on a hand-held calculator, code named "Cal-Tech." It was to be developed as a prototype to show the potential of TI's recently-developed integrated circuits (which were not selling as well as they had hoped). The "Cal-Tech" featured four function calculations (+, -, x, /) and used a thermal paper tape printout.

1967 -- North American Rockwell (USA) begins work on MOS ICs for Japan's Sharp Electronics (then named Hayakawa Electric). Sharp's plan was to reduce the electronic requirements of their desk-top calculator to 4 or 5 ICs: possibly leading to smaller and portable electronic calculators. Texas Instrument's "Cal-Tech" prototype calculator was completed in March 1967. TI would use this as a demonstration tool for their IC design and production capability.

1968 -- Hewlett-Packard releases the fully-electronic model 9100 desk-top calculator, priced at $4,900. The 9100 used a CRT (cathode ray tube) display and was about the size of a large typewriter. Bill Hewlett congratulates the development team but allegedly commented that the world needs a similar machine that would fit in a shirt pocket. Amazingly, the HP engineers would accomplish this new challenge within four years (the HP-35 in 1972)!

1969 -- The first Large Scale Integration (LSI) calculator, Sharp's QT-8, began production using IC chips made by Rockwell. The USA debut of this AC-powered, four function calculator, was at an engineering trade show in New York City in March 1970. It sold for $495 at the time. Work continues between Sharp and Rockwell to reduce the size of the calculator towards a smaller, portable unit. A later version of the QT-8 (the QT-8B from 1970) included a rechargeable battery pack in order to make it portable.

1969 -- Impressed with the "Cal-Tech" prototype and Texas Instruments' IC production capability, Canon (Japan) begins work with TI on the electronics for a small, hand-holdable calculator which would be called the "Pocketronic."

1969 -- Busicom (Japan) contracts with both Intel (USA) and Mostek (USA) to develop ICs for an electronic calculator. Intel completes the task with a single microprocessor chip, the 4004, which is used by Busicom for a desk-top electronic calculator. Intel eventually buys back the rights to the 4004 for use in other devices. The modern-day Pentium IC links back to this early calculator chip. Meanwhile, Mostek develops a complete "calculator-on-a-chip" which will be used in Busicom's first hand-held model (Handy LE-120) later in 1971.


1970's The Pocket Calculator Revolution

1970 -- The first battery-operated "hand-held" calculators are sold. Most are too large to actually be considered "pocket calculators," but they are far smaller than anything seen before. In mid-1970, Sharp begins to sell the QT-8B which, by using rechargeable batteries, is a portable version of their desk-top QT-8. Canon's "Pocketronic" sales begin in the Fall of 1970 in Japan and February 1971 in the USA. Canon used Texas Instruments' ICs and thermal printer. Selling for just under $400, the "Pocketronic" was a four function, hand-held, printing calculator, with the only display being the printed tape running out of the side of the machine. It looks much like the "Cal-Tech" prototype (see 1965). The unit was rechargeable, used a disposable tape cartridge, and weighed 1.8 lbs. Later that year, Sharp begins to market the EL-8, a "small" hand-holdable calculator with four function calculating power, 8 numeric tubes for a display, and rechargeable batteries. Redesigned from the QT-8 series, the unit is smaller and weighs 1.7 lbs. It was marketed in Japan as early as late 1970, but USA advertisements began in February 1971, pricing it at $345. An AC-only version (without the batteries) cost $299.

1970-71 -- Sanyo (Japan) markets a large, portable calculator, the ICC-0081, with 4 functions, rechargeable nicad batteries, and an 8 digit tube display with a flip-up display cover. The unit listed for $425. Sanyo also made a smaller unit (the ICC-802D) for Dictaphone (USA) to sell as the Dictaphone 1680 (in 1970). Sanyo would also label their ICC-804D model as the Dictaphone 1681.

1971 -- In the Fall, Bowmar (USA) begins shipping their first "cigarette pack" sized calculator, the 901B. Priced initially at $240, it was the lowest priced unit on the market and was also one of the smallest. It featured the standard four math functions, an 8 digit red LED display, and rechargeable batteries. The integrated circuit (IC) and Klixon keypad were both made by TI, which was then solely a parts supplier -- not a rival calculator manufacturer. Craig (USA) and Commodore (England) also sold the Bowmar-made calculator under their own labels (as models 4501 and C110 respectively) at the same time. Bowmar, until then a LED maker, introduced this first model to potential distributors at a business trade show in May. Bowmar would go on to become the leading producer and marketer of pocket calculators in the USA before their unfortunate slide into bankruptcy in the mid-1970's. Also in 1971, Busicom (Japan) introduces the Handy LE-120A, the world's smallest hand-held calculator, to that point in time. Brother (Japan), Addo (Sweden), and a few other companies begin making portable models.

1972 -- Scores of companies rush into the pocket calculator business as demand for this amazing new product soars. Prices begin to fall as competition grows. Average price for a basic four function model is down to about $150 by the end of the year. A few models, including those by Casio (Japan), Rapid Data (Canada), and Digitrex, sell for below $100. In December of 1972, TI files a patent application for the hand-held calculator with the inventors listed as Jack Kilby, Jerry Merryman, and James Van Tassel. HP introduces their first pocket calculator, the HP-35, the world's first pocket calculator with scientific (transcendental) functions. Slide rule sales plummet.

1973-74 -- Competition to produce cheaper pocket calculators reaches a frenzy. Many models begin to sell for under $100. Some calculator companies, unable to reduce their costs enough, are forced out of business.

1974 -- On June 25, 1974, the U.S. Patent office grants Texas Instruments the patent (3,819,921) for a "miniature electronic calculator." However, years of international debate would continue and Japan will not grant TI a similar patent until 1978.

1975 -- The pocket calculator is widely used by students as some simple four-function calculators break the $20 price barrier. Controversy flares as some teachers demand that the devices be banned from classrooms for fear that students will not learn math. Almost anyone can now afford a new technology that was not available only five years earlier.

1976 -- Liquid crystal displays (similar to those used in today's pocket calculators) are finally refined and reliable enough for common usage. LCDs had some moderate use on calculators as early as 1972 (see models by Lloyds and Sharp) but manufacturing and reliability issues limited their use. LCD displays use far less current than LED or fluorescent models and allow a pocket calculator to run for months rather than hours without charging or changing batteries.

1977 -- The TI-30, perhaps the most common LED scientific calculator ever made is now selling for under $20. LCD models become more common.

1978 -- LCD calculators begin to capture the market with their simple, compact cases and multiple functions. Also, solar-powered calculators are becoming more available. Power-hungry non-LCD models are becoming obsolete. The pocket calculator becomes a common household item as some simple function calculators break the $10 price barrier.

1979 -- Stores begin to liquidate their remaining stock of LED and fluorescent pocket calculators. In July, HP introduces their final LED models along with their first LCD model (the HP-41C). The end of the decade symbolically marks the virtual end of the line for pocket calculators using LED and fluorescent displays.

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© Text & photographs copyright Nigel Tout   2000-2017  except where noted otherwise.