|Reference||STATE OF THE ART||Stan Augarten|
|Solid-State Electronics Goes Commercial|
The Junction Transistor
For all their magic, point-contact transistors had significant drawbacks. Each transistor processed slightly different electrical characteristics - a maddening quality that had to be eliminated if the invention were ever to become a commercial entity. William Shockley, who had headed Bell's semiconductor program but had not shared in the patent of the point-contact transistor, immediately set out to develop an improved version, and the result is the unsightly object on the right.
The junction transistor was a cylindrical plug of germanium that had been impregnated, or doped, with chemical impurities to enable it to carry a charge. It was an electrical sandwich of sorts: the upper and lower sections, the collector and emitter, were doped with an element containing an excess of positive ions, while the region in the middle, the base, was doped with an electron-bearing element. (Two other commonly used names for Shockley's creation are the positive-negative-positive or pnp transistor, and the bipolar transistor. Transistors of the npn variety were made later; see pp. viii - ix.)
The invention was a great success. Not only was the junction transistor much more stable and reliable than its predecessor, it was also substantially easier and cheaper to make. Bell Labs freely licensed the device to other manufacturers, and it gradually supplanted the vacuum tube. By 1952, the U.S. Army was buying about five thousand transistors a week (and paying premium process for them, too), and the first commercial applications of the device, as amplifiers in hearing aids, came in 1953.
At first, transistors were quite expensive. Texas Instruments (TI), one of the early manufacturers, sold germanium transistors for $6 each, at a time when vacuum tubes were going for a dollar or less. Yet transistors were so superior to tubes, consuming infinitely less energy and giving off almost no heat, that their predominance awaited only reductions in cost. By the mid-1950s, TI had gotten the price down to $2.50, and the first portable transistor radio, made by a company called Regency, went on sale for $49.95.
|The junction transistor is a mudlike substance in the center of the board. The wire on the left is attached to the emitter and is grounded; the wires on the right are attached to the base and the collector. (A re-creation.) Actual size of the transistor: .50 inches tall.|
|STATE OF THE ART
©Copyright Stan Augarten
|This book is provided for general reference. The National Museum of American History and the Smithsonian Institution make no claims as to the accuracy or completeness of this work.|
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