At Bell Telephone Laboratories on December 16, 1947, physicists John Bardeen and Walter Brattain attached three flimsy metal contacts to a thin sliver of the element germanium, applied an electric signal, and discovered that the signal emerging from their device was nearly a hundred times stronger than the one that went in. Unveiled a week later to Bell Labs executives, the new solid-state amplifier-soon dubbed a "transistor"-was "a magnificent Christmas present," in the words of research group leader William Shockley, who only a month later conceived an improved version that eventually proved far easier to manufacture.

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