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Great Inventions: The Pocket Calculator

October 26, 2010
by Lindsey Chapman
Since the time when people used the abacus or slide rule to perform arithmetic, scientists have been looking for easier ways to make calculations. Their task was made considerably easier when Jack Kilby helped spur the invention of the pocket calculator.

The Pre Calculator Era

Before the advent of the pocket calculator, scholars, mathematicians, scientists (and maybe a geek or two) were mathematically empowered by the slide rule. For centuries these tools were important to industry, academic disciplines such as science and math, and even European royalty. They helped people conduct business and develop inventions like the steam engine.

But as often happens with technology, the slide rule was made obsolete by far superior instrument: the pocket calculator.

Jack Kilby

Calculators would not have gotten their start without the help of American engineer and physicist Jack Kilby. As a newcomer to Texas Instruments in 1958, Kilby was left behind as his coworkers took time off for a summer break. During the intervening period he was determined to solve a problem: simplify clunky electronic devices.

Several years earlier, Bell Laboratories devised a transistor that eliminated the need for vacuum technology in electronics, but the components took time to solder together, and the process was costly.

Kilby wanted to miniaturize electronic components. He created the integrated circuit, or microchip, which is the basis of information technology. Integrated circuits help process large amounts of information in small amounts of time. They also aided scientists in developing computers that could fit into offices and even pockets.

The Calculator Wars Begin

In 1964, calculator company Sharp produced the first “all transistor-diode electronic calculator.” The company had abandoned its original plan of making large computers in favor of creating a machine that anyone could use.

Sharp kicked off a revolution. In 1970, the company released the QT-8D, an electronic calculator using integrated circuits.

Work at Hewlett-Packard

Some of the earliest calculators could perform just the four basic math functions: addition, subtraction, division and multiplication. Hewlett-Packard’s first pocket calculator, the HP-35 had more capabilities, including an “arc” key and a “CHS” key. So named by Bill Hewlett because it had 35 keys, the HP-35 took 20 engineers approximately 1 million dollars and two years to develop.

At Texas Instruments

The integrated circuit is considered Jack Kilby’s most important invention, but he also designed the Pocketronic in 1967, “the first IC-based electronic calculator.” The trouble with the Pocketronic was that it used too many integrated circuits, and was too expensive to manufacture for sale. By 1972, Texas Instruments was able cut back the integrated circuits in the calculator to just one.

That same year, Texas Instruments introduced the Datamath pocket calculator, and by 1976 slide rules were a thing of the past.

Today’s Pocket Calculators

The pocket calculators we use today are considerably more advanced than their early predecessors, performing multiple functions. Kilby’s work has brought considerable changes to electronics.

President Clinton once told him, “You can take pride in the knowledge that your work will help to improve lives for generations to come.”

Of his achievements, Jack Kilby once said, “It’s quite satisfying—hell, it’s incredibly satisfying—to face some important problem and find a solution that works.” He continued, “Yeah, scientists get the theories. But engineers make them work. And the engineer has the added challenge of cost, because if your solution works but it costs too much, there will never be any application.”
In 2000, Kilby, with German physicist Herbert Kroemer and the Russian Zhores Alferov, received a Nobel Prize for his work in electronics.

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