10/23/2023 0 Comments First transistor 1947![]() “A lot of people were confused by the point-contact transistor,” says Thomas Misa, former director of the Charles Babbage Institute for the History of Science and Technology, at the University of Minnesota. Even so, reading it gives you the sense that a few fine details probably eluded even the inventors themselves. John Bardeen’s lecture for that Nobel Prize, in 1956. So it seems appropriate somehow that the most comprehensive explanation of the point-contact transistor is contained within The Art of Electronics by Horowitz and Hill, makes no mention of the point-contact transistor at all, glossing over its existence by erroneously stating that the junction transistor was a “Nobel Prize-winning invention in 1947.” But the transistor that was invented in 1947 was the point-contact the junction transistor was invented by Shockley in 19 48. Indeed, the current edition of that bible of undergraduate EEs, Textbooks and popular accounts alike tend to ignore the mechanism of the point-contact transistor in favor of explaining how its more recent descendants operate. It featured two pieces of barely separated gold foil gently pushed by that squiggly spring into the surface of a small slab of germanium. Sometime late in 1947 they hit on a solution. In the germanium semiconductor they were using, a surface layer of electrons seemed to be blocking an applied electric field, preventing it from penetrating the semiconductor and modulating the flow of current. In November 1947, Bardeen and Brattain were stymied by a simple problem. Both were working under William Shockley, a relationship that would later prove contentious. Somewhat volatile” experimentalist, Walter Brattain. ![]() Its inventors were a soft-spoken Midwestern theoretician, John Bardeen, and a voluble and “ It was an ungainly looking assemblage of germanium, plastic, and gold foil, all topped by a squiggly spring. A third contact, the base, is attached to the reverse side of the germanium. One of these points is the emitter and the other is the collector. In the cutaway photo of a point-contact, two thin conductors are visible these connect to the points that make contact with a tiny slab of germanium. ![]() And relatively little attention has been paid to this gap in scholarship. Modern, more robust junction and planar transistors rely on the physics in the bulk of a semiconductor, rather than the surface effects exploited in the first transistor. Though the point-contact transistor was the most important invention of the 20th century, there exists, surprisingly, no clear, complete, and authoritative account of how the thing actually worked. Starting in 1925, but the first recorded instance of a working transistor was the legendary point-contact device built at AT&T Bell Telephone Laboratories in the fall of 1947. Patents for transistor-like devices had been filed This article is part of our special report on theħ5th anniversary of the invention of the transistor.īut building such a device had proved an insurmountable challenge to some of the world’s top physicists for more than two decades. The field effect was already well known in those days, thanks to diodes and related research on semiconductors. The underlying principle of such a device would be something called the field effect-the ability of electric fields to modulate the electrical conductivity of semiconductor materials. The goal was a three-terminal device made out of semiconductors that would accept a low-current signal into an input terminal and use it to control the flow of a larger current flowing between two other terminals, thereby amplifying the original signal. If a more rugged, reliable, and efficient alternative to the triode could be found, the rewards would be immense. But vacuum tubes were power-hungry and fragile. Not only had the triode made long-distance telephony and movie sound possible, it was driving the entire enterprise of commercial radio, an industry worth more than a billion dollars in 1929. The timestamp is only as accurate as the clock in the camera, and it may be completely wrong.The vacuum-tube triode wasn’t quite 20 years old when physicists began trying to create its successor, and the stakes were huge. If the file has been modified from its original state, some details such as the timestamp may not fully reflect those of the original file. This file contains additional information such as Exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it.
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