National Geographic : 1968 Aug
National Geographic, August, 1968 stroke. A doctor may be able to reactivate the paralyzed limbs by electronic commands. Physicians may also be able to control emo tions of deeply disturbed individuals. Transistors are better than vacuum tubes, and IC's surpass transistors; why not, then, multiply the advantages by combining many different circuits on one silicon slice? A number of electronics firms are racing to do just that. They call it "large-scale integra tion." Using new techniques to crowd com ponents closer and closer, one firm says it can already put nearly a million on a two-inch slice-although it has not yet solved the prob lem of making all of them usable. The me dieval theologians who debated how many angels could dance on the point of a pin had nothing on today's electronics engineers. Computers May Do Household Chores When these supercircuits and "computers on a slice" come out of a laboratory some years hence, the stuff of dreams will become reality. The computer, adaptable to an infinite number of tasks, will become remarkably cheap by today's standards. According to predictions given me by industry leaders, including Dr. Simon Ramo, Vice Chairman of the Board of TRW, Inc., at Redondo Beach, California, here's what it will do for you: * In your car a computer no bigger than a teacup will control your ignition system and all the instruments on your dash. More im portant, it will continuously monitor radar signals that measure the distance to the next car. If the distance becomes too small or the rate of approach becomes too great for safety, an alarm will sound. * In your home, a rented terminal linked to a master computer will virtually run your household. It will control the environment heating, cooling, humidity. It will control all your appliances and radio, hi-fi, and tele vision sets. If you are delayed on a shopping trip, you will be able to phone in and direct the computer to turn on the stove and start dinner. It will figure your income tax and at any moment tell you your balance in the bank. * If you wish, you will even be able to have books in your city library reproduced on a screen in your home, page by page. The books, of course, will have been recorded on magnet ic tape at the library. And your newspaper may one day roll out of a machine in your home, printing news fed into the computer, for a fee, at the newspaper office. * At the department store, the clerk will take your personal identification card, put it into a slot connected by computer to the local banks, and the amount of the purchase will be trans ferred from your balance to the store's ac count. If your balance won't cover the pur chase, the computer will say so. Checks will become obsolete for most purposes. All this can become possible through large scale integration. Crystals Convert Light to Power The marvels we have looked at so far all involve the special properties of semiconduc tor crystals-chiefly silicon. Many other kinds of crystals offer their own unique capabilities. Ruby crystals, for example, can be made into lasers, which amplify light and produce enormously bright and powerful beams.* Some crystals convert light into electricity. Crystalline selenium does this in a photogra pher's light meter (page 280). The amount of light hitting the selenium determines the strength of current it creates, and thus con trols how far the pointer moves across the dial. Many spacecraft wear thousands of thin purple-blue rectangles of silicon. These are solar cells; they provide the spacecraft with electricity converted from sunlight at rates as high as 10 watts per square foot of surface. Piezoelectric crystals, such as quartz or Rochelle salt, give off electricity when twisted or pressed, or vibrate rapidlywhen an alternat ing current is applied. (The name comes from a Greek root meaning to press or squeeze and is pronounced pee-AY-zoh.) At the Bell Telephone Laboratories in Murray Hill, New Jersey, I saw a simple but revealing demonstration of how such crystals work. In an exhibit case, a wafer of quartz is connected to an electric meter. A mechanical hammer periodically strikes the crystal. At each blow, the needle on the meter jumps, showing that a current is passing through. Piezoelectric crystals are used by the mil lions for all sorts of useful tasks. In many phonograph pickups they respond to the vi brations of the stylus in the record grooves by giving off a weak current, whose variations are amplified and sent on to the loud-speaker. They work similarly in microphones. In sub marine sonar systems, they detect sounds. And in radio stations thin quartz wafers vibrating *See "The Laser's Bright Magic," by Thomas Meloy, NATIONAL GEOGRAPHIC, December, 1966.