In the early 1950s a transistor about as big as an eraser cost several dollars. By the mid-1970s, when transistors were approaching the size of a bacterium, they cost mere hundredths of a cent apiece. By the late 1990s the price of a single transistor was less than a hundred-thousandth of a cent—sometimes far less, mere billionths of a cent, depending on the type of chip. In the early 1950s a transistor about as big as an eraser cost several dollars. By the mid-1970s, when transistors were approaching the size of a bacterium, they cost mere hundredths of a cent apiece. By the late 1990s the price of a single transistor was less than a hundred-thousandth of a cent—sometimes far less, mere billionths of a cent, depending on the type of chip. Some chips provide electronic memory, storing and retrieving binary data. Others are designed to execute particular tasks with maximum efficiency—manipulating audio signals or graphic images, for instance. Still others are general-purpose devices called microprocessors. Instead of being tailored for one job, they do whatever computational work is assigned to them by software instructions. The first microprocessor was produced by Intel in 1971. Dubbed the 4004, it cost about $1,000 and was as powerful as ENIAC, the vacuum tube monster of the 1940s. Faster versions soon followed from Intel, and other companies came out with competing microprocessors, with prices dropping rapidly toward $100. Engineers and scientists are exploring three-dimensional architectures for circuits, seeking organic molecules that may be able to spontaneously assemble themselves into transistors and, on the misty edge of possibility, experimenting with mysterious quantum effects that might be harnessed for computation.
1904 Thermionic valve, or diode invented Sir John Ambrose Fleming, a professor of electrical engineering and the first scientific adviser for the Marconi Company, invents the thermionic valve, or diode, a two-electrode rectifier. Building on the work of Thomas Edison, Fleming devises an "oscillation valve"—a filament and a small metal plate in a vacuum bulb. He discovers that an electric current passing through the vacuum is always unidirectional. 1904 Thermionic valve, or diode invented Sir John Ambrose Fleming, a professor of electrical engineering and the first scientific adviser for the Marconi Company, invents the thermionic valve, or diode, a two-electrode rectifier. Building on the work of Thomas Edison, Fleming devises an "oscillation valve"—a filament and a small metal plate in a vacuum bulb. He discovers that an electric current passing through the vacuum is always unidirectional. 1907 Triode patented Lee De Forest, an American inventor, files for a patent on a triode, a three-electrode device he calls an Audion. He improves on Fleming’s diode by inserting a gridlike wire between the two elements in the vacuum tube, creating a sensitive receiver and amplifier of radio wave signals. The triode is used to improve sound in long-distance phone service, radios, televisions, sound on film, and eventually in modern applications such as computers and satellite transmitters. 1940 Ohl discovers that impurities in semiconductor crystals create photoelectric properties Russell Ohl, a researcher at Bell Labs, discovers that small amounts of impurities in semiconductor crystals create photoelectric and other potentially useful properties. When he shines a light on a silicon crystal with a crack running through it, a voltmeter attached to the crystal registers a half-volt jump. The crack, it turns out, is a natural P-N junction, with impurities on one side that create an excess of negative electrons (N) and impurities on the other side that create a deficit (P). Ohl’s crystal is the precursor of modern-day solar cells, which convert sunlight into electricity. It also heralds the coming of transistors.
1947 First pointcontact transistor John Bardeen, Walter H. Brattain, and William B. Shockley of Bell Labs discover the transistor. Brattain and Bardeen build the first pointcontact transistor, made of two gold foil contacts sitting on a germanium crystal. When electric current is applied to one contact, the germanium boosts the strength of the current flowing through the other contact. Shockley improves on the idea by building the junction transistor—"sandwiches" of N- and P-type germanium. A weak voltage applied to the middle layer modifies a current traveling across the entire "sandwich." In November 1956 the three men are awarded the Nobel Prize in physics. 1947 First pointcontact transistor John Bardeen, Walter H. Brattain, and William B. Shockley of Bell Labs discover the transistor. Brattain and Bardeen build the first pointcontact transistor, made of two gold foil contacts sitting on a germanium crystal. When electric current is applied to one contact, the germanium boosts the strength of the current flowing through the other contact. Shockley improves on the idea by building the junction transistor—"sandwiches" of N- and P-type germanium. A weak voltage applied to the middle layer modifies a current traveling across the entire "sandwich." In November 1956 the three men are awarded the Nobel Prize in physics. 1952 First commercial device to apply Shockley’s junction transistor Sonotone markets a $229.50 hearing aid that uses two vacuum tubes and one transistor—the first commercial device to apply Shockley’s junction transistor. Replacement batteries for transistorized hearing aids cost only $10, not the nearly $100 of batteries for earlier vacuum tube models. 1954 First transistor radio Texas Instruments introduces the first transistor radio, the Regency TR1, with radios by Regency Electronics and transistors by Texas Instruments. The transistor replaces De Forest’s triode, which was the electrical component that amplified audio signals—making AM (amplitude modulation) radio possible. The door is now open to the transistorization of other mass production devices.
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