How was the calculator discovered

50 years of pocket calculators: the invention that nobody wanted

It must have driven US physicist Jack Kilby insane more than 50 years ago that his then-employer Texas Instruments failed to properly acknowledge the value of his groundbreaking invention. In the summer of 1958, while his laboratory colleagues were on vacation, he had developed the integrated circuit, the world's first microchip, using improvised equipment. It would take almost another ten years before he was able to show a perspective for the microchip with the prototype of his first pocket calculator.

Nobel Prize in Physics

Kilby came up with the idea of ​​combining transistors, resistors and capacitors in a single circuit based on a semiconductor. In 1958 he mounted the first "integrated circuit" on a glass plate with a piece of germanium and wires attached to it. In 1959, the physicist Robert Noyce also manufactured a microchip in the Californian company Fairchild, choosing a circuit made of silicon. Kilby had his circuit protected with the patent 3,138,743, which was then disputed in court. A comparison was only reached after ten years.

For his invention of the integrated circuit, Kilby was inducted into the Hall of Fame of American Inventors in 1982, and found his place alongside Thomas Edison and the Wright brothers. In 2000 he received the Nobel Prize in Physics. But at the end of the fifties, it wasn't just the TI bosses who found it difficult to specifically recognize the potential of the invention. The ICs were more of a curiosity at specialist congresses, Kilby later recalled.

Thick like a dictionary

In order to be able to present a concrete application example for the microchip, Kilby set out in 1966 with his colleagues Jerry Merryman and James Van Tessel to design the world's first pocket calculator. Fifty years ago, on March 29, 1967, Kilby presented his "Cal Tech" to the director of Texas Instruments. The black aluminum case was almost as thick as a dictionary and weighed two and a half pounds. Even then, it would not have fit in a pocket. But at least it could be operated with batteries independently of the mains.

The "Cal Tech", which has nothing to do with the university of the same name in California, could add, subtract, multiply and divide six-digit numbers. However, the box did not handle more complex functions. And so the TI management team was initially only moderately impressed. For the second time, Kilby had to accept that one of his great inventions was practically ignored.

Series production at Canon

After all, the TI management made it possible for the Japanese company Canon to convert the "Cal Tech" into series production. Canon brought out the "Pocketronic" in Japan in April 1970, in which the numbers were also not displayed electronically, but instead were printed out on a small strip of thermal paper. The computer hit the US market in early 1971 and cost just under $ 400.

In 1971, the "Handy-LE" from the Japanese manufacturer Busicom lit up for the first time with LED digits. In Japan, the Sanyo ICC-82D and the Sharp EL-8 came onto the market at almost the same time. In Germany they cost around 2000 DM (1022 euros) each - that's how much a used car cost at the time.

Price drops in the 70s

But the high prices quickly fell: "In 1974 the first devices were available for less than 100 DM," says Andreas Stolte from the Heinz Nixdorf MuseumsForum in Paderborn. "The HP 35 from Hewlett Packard already made it possible to calculate angle and exponential functions. This first technical-scientific calculator appeared in 1972. In the same year, Texas Instruments finally implemented its own invention commercially and offered the TI-2500 Datamath for sale. "