Santa Clara, CA. The first trans-Atlantic telegraph cable and the birth of electrical engineering as a profession were themes of a story recounted in the DesignCon opening keynote, delivered Tuesday by Thomas H. Lee, professor of electrical engineering at Stanford University. Lee, who according to the event host, owns more than 100 oscilloscopes and thousands of vacuum tubes, said the story is one that EEs should know but seem not to, perhaps because it suggests the not-so-glorious origins of the profession. But in fact, in the face of the severe technical limitations of the time and misguided trial-and-error approaches, the completion of the cable was built on some solid engineering accomplishments, with the innovators of the time even addressing esoteric topics such as inter-symbol interference—still of considerable interest to DesignCon attendees today.
Before delving into the details of the telegraph cable, Lee outlined the marvels wrought by electrical engineering—to the extent that today’s students are jaded by viewing the progress of Moore’s law, from the first 25-μm MOSFET to today’s complex devices. In the ‘60s, he said, we could resolve the individual 2k transistors in an SRAM. Today, he said, we can resolve individual atoms, but on the 60s’ level of magnification, we can barely distinguish functional blocks in a modern IC. In an interesting aside, he said we annually produce 100 transistors for each of the 1017 ants inhabiting the earth.
He then encouraged attendees to “go big or go home.” If you want to spend your time doing something, go for the moon, noting that John F. Kennedy put the U.S. on a path to the moon not because it was easy, and not despite it being hard, but simply because it was hard. That view, Lee said, represents an extraordinary philosophy that can take civilization to the next level.
He then introduced an equation G = f (M, I, L, C) in which G equals greatness, M equals money, I equals ignorance, L equals luck, and C equals craziness. MILC, he said, played a big role in the long effort to build a trans-Atlantic telegraph cable that actually worked.
The project, Lee said, began with Cyrus West Field, who made a fortune turning around a failing paper mill and retired at age 33, providing the M in the equation. With Mr. Field continually under foot, as Lee tells it, Mrs. Field encouraged him to pursue a new career that required extensive long-distance travel. He became involved in an effort to extend telegraph lines to Newfoundland and, glancing at his globe, concluded that Ireland was only a bit further (providing the equation’s I).
As luck (L) would have it, Matthew Maury had just completed an ocean sounding, and it turned out that the ocean floor between Newfoundland and Ireland was not too inhospitable to the deployment of an undersea cable. In an additional bit of luck, it had been discovered that gutta-percha would act as a good underwater insulator. In fact, water improved its insulating properties. Lee asked rhetorically, how often does water improve the electrical properties of anything?
One problem did present itself: how to transmit a signal 3,000 miles without amplification. William Thomson (Lord Kelvin) developed the mirror galvanometer, which could detect weak signals at the receiving end.
Work proceeded in the 1850s, with sailing ships deploying the one-inch-diameter cable, which frequently snapped. The work was finally completed in 1858, but performance, with an RC time constant of 30 seconds, was poor. A medical doctor named Edward Orange Wildman Whitehouse advised raising the transmitted voltage, but at about 1,500 V the cable failed completely.
At that point, Lee said, “cable denial” set in and investors began to think Field had defrauded them.
But investors were willing to try again and sought advice. Samuel F. B. Morse (a painter, by the way) advised making the center conductor of the new cable smaller—a large conductor, he surmised, would make the electricity flow too slowly, thereby adding some craziness (C) to the project. Sometimes it’s hard to distinguish ignorance from craziness—Lee pointed out the terms M, I, L, and C are not orthogonal.
Other participants were getting smarter, though, and they realized they even lacked the vocabulary to describe what had caused the original failure. There wasn’t even a formal definition for the volt, so the volt, ampere, and ohm were defined. Thomson realized that the cable would need to be large to minimize attenuation.
Unfortunately, sailing ships could not handle the larger cable. But luck came into play again. The SS Great Eastern steam ship had been completed, able to carry passengers from England to Australia without refueling. However, the builders of the ship had not conducted adequate market research. It turned out there was little demand to get from England to Australia without refueling, so the underused ship could be pressed into service to deploy the cable.
Finally, the cable was a success. The transmitter schematic fits onto one PowerPoint slide: it includes a 150-V power supply and a 30-nF “condenser” to limit intersymbol interference, Lee said. The line could accommodate eight words per minute, exceeding the five-words-per-minute estimation of Thomson, who had calculated—not guessed at—that figure. The project in its many stages (and failures) had forced electrical engineering to evolve from a hobby into a profession—to grow up.
Lee concluded by asking, “What’s next? The Internet of Things? Telepathy? Who knows, but history is not over.” Whatever is next, he advised DesignCon attendees, “You’re going to be making it. And you’ll need lots of MILC. I hope nature gives you as much as you want or need.”
See related commentary.
-Extend_battery_and_shelf_life_without_compromising_system_performance.png?auto=format,compress&fit=crop&h=139&w=250&q=45)
_Cables.PNG?auto=format,compress&fit=crop&h=139&w=250&q=45)
