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History of Transistors
Before transistors, vacuum tubes were used as controlling devices in electronic circuits. These tubes were large, bulky and inefficient; as a result, scientists looked for alternative solutions. In 1947, William Shockley, John Bardeen and Walter Brattain developed a working transistor at Bell Laboratories. Early transistors were made of germanium, although later models improved upon this by using silicon, a much cheaper and usable material. Commercial companies started producing transistors in the 1950s, and vacuum tubes soon became obsolete.
What is a Transistor?
A transistor is a semiconductor device that is used to amplify and switch electronic signals. It is made out of a semiconductor material such as silicon, and contains at least three terminals to connect to a circuit. The nature of a transistor allows the output power to be much greater than the input power; this allows it to amplify signals and control a large signal with a small one. In addition, transistors can be used as switches, turning current on or off within a circuit.
Transistors and Technology
Because transistors are small and made of silicon, a cheap material, they can be mass produced through a highly automated process known as semiconductor device fabrication. Unlike their vacuum tube predecessors, transistors are tiny, and research continues to shrink the size of transistors every year. Most transistors, as of 2011, are produced in integrated circuits, which can contain billions of transistors and many other electronic devices. The number of transistors correlates with the capabilities of an electronic device; as a result, the increasing number of transistors in electronic devices has resulted in constantly improving technology.
Moore's Law
In 1965, Intel co-founder Gordon Moore published a paper that has predicted the growth of transistor technology for the past half century. Known to many as "Moore's Law," the paper essentially states that the number of transistors that can fit on a chip doubles every year. Because transistors are constantly shrinking, companies can fit more and more on the same size chip, effectively doubling a chip's power every year. Although this trend has existed for a long time, transistor technology is approaching a plateau, according to arstechnica.com, as current transistors are so small that power density and heat accumulation are real problems that researchers must deal with now.