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Cal-Tech

TEXAS INSTRUMENTS CAL-TECH PORTABLE CALCULATOR PROTOTYPE 1965-1967

caltech

Sold for US $ 68,825 (€ 57,918) 05/11/2020 Provenance: from Jerry Merryman's estate.

  • "Silly me, I thought we were just making a calculator, but we were creating an electronic revolution" Jerry Merryman on NPR's All Things Considered, 2013.


Original hinged case in milled aluminum finished in black, 155 x 105 x 43mm, 18 button keypad including zero bar, number reading window, power switch, power charger plug, opens to reveal a series of 4 panels large scale transparent cover Integration of silicon "slices" and 3 shift register chips on a printed circuit board, thermal printer with thin paper roll, black plexiglass panel covering the potted battery pack and discretionary circuitry for the supply engraved on the bottom: "SC / 4USE".

Texas Instruments President Patrick Haggerty had found great success a decade earlier when he came up with the idea of ​​miniaturizing the radio using TI's new transistors. Pocket radio quickly became a pervasive technology that introduced consumers to transistors and the wonders of miniaturization, but which also caught the attention of IBM chief Thomas Watson, Jr. who insisted his engineers use transistors. on company computers. TI has become one of IBM's leading chip suppliers.

caltech insideHaggerty had this in mind when, in 1965, he was brainstorming with his deputy director of semiconductor research Jack Kilby, one of the inventors of the integrated circuit (IC) who would later receive the Nobel Prize for Invention. Haggerty wanted a new product, a "killer app" indeed, that would help sell the IC to consumers, which until then had been primarily used for military purposes where the benefits of miniaturization outweighed the costs. Haggerty had pitched a few different product ideas, but it seemed to Kilby that the battery-powered portable calculator was the viable product. He started to put together a team and chose Jerry Merryman of the semiconductor research and development department as the project manager. To keep the project secret, they used a code name. An earlier research project had been codenamed "Project MIT", so in keeping with that line, this became known as "Cal-Tech" although it had nothing to do with the research university. Kilby later admitted that it was a bad choice for a name and that it would be easy to determine what the team was developing.

Merryman, who had attended Texas A&M but hadn't stayed long enough to get a degree, had a reputation as a problem solver and was frequently consulted by his peers. Even Patrick Haggerty stopped to pass ideas to the brilliant electrical engineer. It was the perfect choice for a projecaltech prototypect where nothing could be taken off the shelf, everything had to be developed from scratch. There were no ready-made keyboards, low-power printers, and ICs as complex as what would be required for a portable calculator.

caltech memoryIn a 72-hour marathon design session with limited sleep, Merryman was able to completely trace the logic of the calculator on paper (a copy of which is included in this lot). To test the design, he and his colleagues filled a room with an enlarged version using commercially built integrated circuits. The setup was also used in the end to test each of the new ICs.

Merryman and his team would spend nearly 2 years developing every aspect of the car. Dr James Van Tassel, the other major player on the project, solved the keyboard problem and many other manufacturing problems. Integrated circuits have proved to be one of the main obstacles. At the time, the most complex integrated circuit you could buy had around 20 transistors on it. Merryman's 4-chip draw would require around 8,000. In an article in Invention & Technology, Merryman recounts the story of going to TI's chip-making facilities with his circuit layout and telling them he wanted an 83-percent yield - this is, he wanted 83 percent of the eight-transistor NAND gates in a chip to work. "They all fell on the floor laughing, saying 'We've never seen anything better than 25 percent.'" Merrymen explained his approach to them: "I'm going to be using low-power circuits and very wide tolerances in the voltages and currents that'll work and simple layouts and wide conductors and so on." Merryman also increased the odds of getting a usable chip by including more than twice the NAND gates than what were actually needed.

The chips, actually thin circular silicon wafer slices, proved unreliable despite the precautions. The team went back and used a microscope to trace the connections, find the problems and repair them - all on a less than 1-inch diameter chip. Whereas most chips of the time contained 14 or 16 leads connecting them to one another, these had 122, which required Van Tassel to develop a package that would protect the structure and facilitate connection.

Kilby, Merryman and Van Tassel were ready to apply for a patent in September 1967 and after two revisions, in 1971 and 1972, received U.S. Patent No. 3,819,921 on June 25, 1974 (a copy of which is included in the lot).

Although completed in 1967, the electronics were so advanced for the time that it took years for a production model to be issued. Canon had bought the rights to issue the calculator which they did with their Pocketronic issued on April 14, 1971. The 4-function calculator that weighed 2 1/2 pounds and cost $150 was a huge success. 5 million pocket calculators were sold in the US in 1972 and sales continued to grow as the costs came down. "As Haggerty had predicted, the new microelectronic gadget created a market that had simply not existed before. Tens of millions of people who never considered purchasing an adding machine or a slide rule decided they wanted to own a pocket calculator" (Reid p 137).

This consumer interest in microelectronics would continue as the IC was developed to create the microprocessor. "Patrick Haggerty had been proven right. Microelectronics did pervade nearly every aspect of society, replacing traditional means of control in familiar devices and creating new aspects of human activity that were previously unknown. By shrinking from the room-sized ENIAC to the pinhead-sized microprocessor, the computer had imploded into the basic fabric of life" (Reid p 145).

May, Mike. "How the Computer Got Into Your Pocket," in Invention & Technology Spring 2000; Reid, T.R. The Chip. 1984; Zygmmont, Jeffrey. Microchip. 2003.