"Technology's Past," 1994-1995
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Charles Wheatstone and the Resistance Bridge ECHNOLOGISTS are often so special Irony pervades this Briton's life-his Tized that it is uncommon to find one name is always attached to .some who succeeds at a wide variety of activi thing he didn't Invent, while one ties. Charles Wheatstone, however, a of hi.s inventions bear.s the member of the Royal Society, and name of another. knighted by Queen Victoria, invented the accordion-like concertina, had an connect two cities, linked Liverpool with operational telegraph system five years Manchester. Their system was adopted before Samuel Morse, invented the ste by the British railways. Wheatstone also reoscope, and developed a secret code. invented a printing telegraph and was This ASE preparation program But he is best known for an electrical the first to experiment with underwater includes: , 1 , circuit that accurately measures resis cables. 1 tances, which he didn1t invent. He is most commonly identified with • serv. ice1manuals. • tests 1 WheO.tstone was born in Gloucester, the Wheatstone bridge for measuring ' England, in 1802. His father taught resistance, a cirruit he did not develop • answe~ keys . music and made and and one for which he • certific~tes sold instruments, which never claimed credit. introduced young His close friend, (419j 535-4285 Wheatstone to music, Samuel Hunter, actu ' ' sound transmission, and ally devised it in Dana Corp. f School Publications wave propagation. Al 1833. ·Wheatstone's 800CFI' ankee Road ; though apprenticed to name became asso Ottawa Lake, MI 49267 ' : an uncle in the music ciated with the bridge business, he had no for pecause he often used mal technical instruc it in his experiments. Circle No. 1 3 tion and earned his liv His legitimate accom ing making and selling plishments included instruments with his inventing the rheo brother. stat and improving Wheatstone's early de generators. He years produced no out also discovered that standing inventions or the Earth's magnetic discoveries, but gave field was strong him a series of moder Photo reproduced by permission of the enough tostartagen ate successes. He built Trustees of the Science Museum erator. small experimental pipe Charles Wheatstone Of all Wheat- organs to analyze their stone1s accomplish ' air columns; he examined light given ments, perhaps the most colorful was off by burning metals, now called spec his invention of a secret code, or cipher. Techl Direclia'ns trum analysis; he measured the speed of Cryptography was a hobby of his, and Binders: he came up with a simple, reasonably electrons in a conductor and tried to Handsome, Inotebook-style wire slow down a spark; and he occasionally secure cipher in 1854. In an ironic binders hold 1 O issues of Tech Di 0 wrote technical papers and made pre twist of fate,.itwas named for his friend, rections. Dark blue with gbld Tech sentations. Wheatstone received reward Lyon Playfair, who resembled him so Directions logos, these binders look for his accomplishments in 1834 when much that his wife once confused the great on desk or bookshelf: and will he became professor of experimental two. Almost a century later, when fohn help you kee1p track of all the infor physics at King's College in London. F. Kennedy's torpedo boat was de mation Tech dlirectionsI provides. you Because he was so shy, Wheatstone stroyed in the South Pacific, he used the during the year. · spent most of his time with laboratory Playfair cipher to send for help. I , Lisi price: $13.00; School price: $.10.61 experiments. His most significant suc Wheatsone died in Paris in 1875, where TD PRO Club members: cess was.inventing a telegraph. He was he was a member.of the Paris Academy $6.05 witr membership nUmber trying to transmit audio speech but com· of Sciences. ml promised with a visible speech method. Send check lor money order in the appropriate amount to: Instead of using dots and dashes, Dennis Karwatka is a professor, Depart Wheatstone's telegraph, invented with ment of Industrial Education and Technol Prakkkn Publications William Cooke, used five needles to point ogy, Morehead (KY) State University. Some P.<D. Box 8623 Ann Arbdr, Ml 48107·8623 out specific letters. The partners received information for this column was obtained For credit card orders.I call: a joint patent in 1837. Two years later, through research sponsored by Morehead 1-800530.WORD' their telegraph, the first in the world to State University. I I I TECHNOLOGY'S PAST 1 3 I :. ·f , John Ambrose Fleming ! I AutoCAD S the nineteenth century merged The technologist ~ho opened I Awith the twentieth, electronics be the air waves I and its Applications gan to reveal its secrets. But only those Basics-Release 13 with the talent to interpret subtle ex Marcon1 ·d· es1gn a powerI 1u1 wire·1' ess perimental results could read the signs. transmitter at PoldhuJ in southwestern This highly acclaimed title is One such talent was john Ambrose England. That transmitter sent the first now available current with Fleming, inventor of the first practical transatlantic radio siQnal to St. Jol].zi's, Release 131 Available in a radio tube. Newfoundiand, on December 12, 1901. DOS and Windows edition, Fleming was born in Lancaster, En It was the lei.ter S-thr'ee dots in Mol-se these books provide complete gland, in 1849, but the family moved a code-repeated over a'n.d over. l instruction for mastering the few years later to London. His father The signal was weak and difficult to ' . ' basics of AutoCAD. In-depth was a minister, detect, and Fleming th~ughtaboutways discussions of AutoCAD fea and his mother to improve radio circuitry. The result! in tures and commands are cou came from a 1904, was the tube-typ'e diode. Based'on pled with hundreds of exercis the Edison effect, alt~rnating current es, questions, and drawing family that de entered the device, bJt only direct ci.tr problems. The complete veloped the teaching package includes a manufacture of rent left. Fleming called it a valve, since Solution Manual, Work Disks, Portland ce it turned on for rurrent~ flow in one di~ec and Transparency Packet! ment. _Fleming tion and turned off for:flow in the otner. had excellent His invention allowedl more precise O.e For more information contact: public school tection of radio waves and was heavilf education and used in early radio coPimunication.: lillli!1I GOODHEART-WILLCOX graduated from Like Edison, he . ~ 800-323-0440 the University was almost deaf, Circle No~ 9 John Ambrose College of Lon and he said that Fleming don (UCL). His deafness height academic work ened his powers of earned him a position as "demonstrator con·cen trc;i ti on. of mechanisms and applieCi mechan Heming was a cap ics" at Cambridge University. tivating speaker, He later taught at a Nottingham col often making pub lege and was a consultant forthe Edison lic presentations, Electric Light Company. In 1885, he his last at the age became professor of elt?ctrical technol of 90. He wrote two ogy .at UCL, where he worked for 41 textbooks, a biog years. An outstanding teacher, Fleming raphy, and many also worked on carbon filament lamps, technical papers which had a short life and darkened and received many with use. Thomas Edison had tried to awards, including a improve the bulb by placing an elec knighthood. trode next to the filament. Positive volt Fleming's e1ec· age to the electrode produced a small tronicvalve laid the current that flowed between it and the groundwork for Lee filament. This was later called the Edison Deforest' s triode effect. Edison patented this-he patented amplifier ("Tech- o~e of Flem,ing's nology's Past," 1or1glnaltube.:.type everything-but did no more with it. 1 In 1889, Fleming began to research April 1983) and diodes. ' the phenomenon, experimenting with ushered in practi- I electrical conduction between filaments cal electronic communication. It is still in_a vacuum. He carried out countless used in television pitture tubes, com- ' ·. experiments on wireless transrriission puter screens, and radio transmitters. and reception. Though Fleming had a Fleming died in 1945 Jat 95. llll flair for linking complex electrical math ematics with their practical effect, his Dennis Karwatka is dprofessor, Depart research seemed to.lead nowhere, and ment of Industrial Educhtion and Technol he left it for several years. ogy, Morehead (KY) Sta:te University. Some Fleming became a technical advisor information for this colUmn was obtained to his friend", Italian radio developer through research spomored by Morehead Guglielmo Marconi, in 1899. He.helped Statf -~niversity. I ! Circle No. 1 0 8 Tech Diteclians • October 1995 ; · MSU ARCHIVES 1 ?51f't-t5J.J'i ' Stephenson's Railroad Rocket \ ! ITH steam engines powering more The rallway age began with the first Wand more factories in the early modern loco.rtotlve. , 1800s, the need for coal increased, and . · 1 I 1 horse transportation could not keep up ered locomotives, not winding engines• with the deµiand. Technologists consid- That was a gamble becauseI no one' ered steam engines to transport coal, knew how effectively m1etal wheels oii developing several promising locomo- metal rails could haul ~eavy loads up tives, but George Stephenson's 1829 hills. Just in case, Steph~nson dug long Rocket launched the railway age. trenches and tunnels along the route Stephenson was born in 1781 near to level the rail- I : Newcastle, in an important English coal bed. The difficult mining area. He began working in a project took five mine at a young age. Receiving n_o for- years. mal education, he was illiterate until 18 LMR officials and never read well as an adult.