History Software Engineering

First Transistorized Computer – 1953 AD

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First Transistorized Computer

Tom Kilburn (1921–2001), Richard Grimsdale (1929–2005), Douglas Webb (b. 1929), Jean H. Felker (1919–1994)

“With the invention of the transistor in 1947, the next step was to use it as a replacement for the vacuum tube. Tubes had a significant advantage compared to relays—they were a thousand times faster—but tubes required an inordinate amount of electricity, produced huge amounts of heat, and failed constantly. Transistors used a fraction of the power, produced practically no heat at all, and were more reliable than tubes. And because transistors were smaller than tubes, a transistorized machine would run inherently faster, because electrons had a shorter distance to move.

The University of Manchester demonstrated its prototype transistorized computer on November 16, 1953. The machine made use of the “point-contact” transistor, a piece of germanium that was in contact with two wires held in very close proximity to each other—the two “points.” The Manchester machine had 92 point-contact transistors and 550 diodes. The system had a word size of 48 bits. (Many of today’s microprocessors can operate on words that are 8, 16, 32, or 64 bits.) A few months later, Jean H. Felker at Bell Labs created the TRADIC (transistor digital computer) for the US Air Force, with 700 point-contact transistors and more than 10,000 diodes.

This point-contact transistor was soon replaced by the bipolar junction transistor, so named because it is formed by a junction involving two kinds of semiconductors. Manchester updated its prototype in 1955 with a new design that used 250 of these junction transistors. Called the Metrovick 950, that computer was manufactured by Metropolitan-Vickers, a British electrical engineering company.

In 1956, the Advanced Development Group at MIT Lincoln Lab used more than 3,000 transistors to build the TX-0 (Transistorized eXperimental computer zero), a transistorized version of the Whirlwind and the forerunner to Digital Equipment Corporation’s (DEC) PDP-1.”

SEE ALSO William Shockley’s Silicon Transistor (1947), Whirlwind (1949), PDP-1 (1959)

Close-up of the prototype of the Manchester transistorized computer.

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History Software Engineering

William Shockley’s Silicon Transistor – 1947 A.D.

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Silicon Transistor

John Bardeen (1908–1991), Walter Houser Brattain (1902–1987), William Shockley (1910–1989)

“A transistor is an electronic switch: current flows from one terminal to another unless voltage is applied to a third terminal. Combined with the laws of Boolean algebra, this simple device has become the building block for microprocessors, memory systems, and the entire computer revolution.

Any technology that can use one signal to switch another on and off can be used to create a computer. Charles Babbage did it with rods, cogs, and steam power. Konrad Zuse and Howard Aiken did it with relays, and ENIAC used tubes. Each technology was faster and more reliable than the previous.

Likewise, transistors have several advantages over vacuum tubes: they use less power, so they generate less heat, they switch faster, and they are less susceptible to physical shock. All of these advantages arise because transistors are smaller than tubes—and the smaller the transistor, the bigger the advantage.

Modern transistors trace their lineage back to a device manufactured by John Bardeen, Walter Brattain, and William Shockley at AT&T’s Bell Laboratories in 1947. The team was trying to build an amplifier that could detect ultra-high frequency radio waves, but the tubes that they had just weren’t fast enough. So they tried working with semiconductor crystals, as radios based on semiconductor diodes called cat’s whiskers had been used since nearly the birth of radio in the 1890s.

A cat’s whisker radio uses a sharp piece of wire (the “whisker”) that’s jabbed into a piece of semiconducting germanium; by moving the wire along the semiconductor and varying the pressure, the semiconductor and the wire work together to create a diode, a device allowing current to pass in only one direction. The Bell Labs team built a contraption that attached two strips of gold foil to the crystal and then applied power to the germanium. The result was an amplifier: a signal injected into one wire was stronger when it came out of the other. Today we call this device a point-contact transistor.

For their discovery of the transistor, Bardeen, Brattain, and Shockley were awarded the Nobel Prize in 1956.”

SEE ALSO Semiconductor Diode (1874), First LED (1927)

“The first transistor ever made, built in 1947 by John Bardeen, William Shockley, and Walter H. Brattain of Bell Labs.”

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Semiconductor Diode – 1874 A.D.

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Semiconductor Diode

Michael Faraday (1791–1867), Karl Ferdinand Braun (1850–1918)

“Semiconductors are curious devices: not quite conductors like copper, gold, or silver, not quite insulators like plastic or rubber. In 1833, Michael Faraday discovered that the chemical silver sulfide became a better conductor when heated, unlike metals that lose their conductivity under the same conditions. Separately, in 1874, Karl Ferdinand Braun, a 24-year-old German physicist, discovered that a metal sulfide crystal touched with a metal probe would conduct electricity in only one direction. This “one direction” characteristic is what defines diodes or rectifiers, the simplest electronic components.”

“In 1904 the British chemist John-Ambrose Fleming had invented the two-element amplifier, or ‘diode’, and a few months before DeForest the Austrian physicist Robert von Lieben had already built a three-element amplifier, or triode.” (Fair Use: B07XVF5RSP)

“Braun’s discovery was a curiosity until the invention of radio. The diode proved critical in allowing radio to make the transition from wireless telegraphy to the transmission and reception of the human voice. The diode of choice for these early radio sets was frequently called a cat’s whisker diode, because it consisted of a crystal of galena, a form of lead sulfide, in contact with a spring of metal (the “whisker”). By carefully manipulating the pressure and orientation of the metal against the crystal, an operator could adjust the electrical properties of the semiconductor until they were optimal for radio reception. Powered only by the radio waves themselves, a crystal set was only strong enough to faintly produce sounds in an earphone.”

“Crystal radio receivers were used onboard ships and then in homes until they were replaced by new receivers based on vacuum tubes, which could amplify the faint radio waves so that they were strong enough to power a speaker and fill a room with speech or music. But tubes didn’t mark the end of the crystal radio: the devices remained popular for people who couldn’t get tubes—such as on the front lines in World War II — as well as among children learning about electronics. In the 1940s, scientists at Bell Labs turned their attention to semiconductor radios once again in an effort to perfect microwave communications. In the process, they discovered the transistor.”

“Braun went on to make other fundamental contributions to physics and electronics. In 1897, he invented the cathode-ray tube (CRT), which would become the basis of television. He shared the 1909 Nobel Prize with Guglielmo Marconi (1874–1937) “in recognition of their contributions to the development of wireless telegraphy.””

SEE ALSO: Silicon Transistor (1947)

Crystal Detector, made by the Philmore Manufacturing Company. To use this device, the operator would connect a wire to each of the two flanges and press the metal “whisker” into the semiconductor crystal.”

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