BBC News Online: Sci/Tech

Fifty years of the invention that launched the information age

Gadgets and appliances rely on transistors to function. Microchips contain thousands, or sometimes millions, of tiny transistors.

Without the transistor many of the everyday electronic items we take for granted would not exist.

The transistor has two basic applications. The first, modulation of an electronic current, came first in the form of an amplification of an electric signal in a radio.

The second application, switching, is of great importance in computer operations, which are based on millions of lightning fast on-off decisions.

The transistor is an integral component of an integrated circuit, the brains of a computer.

Neil Johanneson, of the British Telecom museum in London, said: "Looking around, if you took out all the transistorised equipment you might be left with the lights and the carpet.

"Videos, portable radios, mobile phones - without transistors all of those would never really have come about."

In the 1940s families used to gather round large, expensive radio sets to hear the news.

Radios contained valves or vacuum tubes which, at the time, were the only way of controlling and amplifying an electrical signal.

But valves were fragile, bulky and costly to produce. Something better was sorely needed, and it was discovered by a team of physicists at Bell Laboratories in the United States.

December 16,1947, saw the climax of 18 months of very intense work by physicists John Bardeen and Walter Brattain who were working in a team under William Shockley.

Physicist Lillian Hoddeson, who has written a book about the birth of the transistor, said the first transistor was "a very hairy object," with wires sticking out in every direction and a bent paper clip.

"It was a laboratory device, it could not have been used in anything.

"At a certain moment they pressed down and they turned on the current and they noticed that they had voltage amplification of approximately 100, and that was a great moment."

The three were awarded the Nobel Prize in physics in 1956.

The first transistors were about the size of a matchbox. If today's powerful computers were built from these they would be bigger than football pitches. So the next step was to find something more compact.

The integrated circuit was a response to the problem of putting together many transistors in complicated circuits.

All of the elements were made of silicon and were etched on to a chip of silicon.

All that remained was for an electronics giant to emerge and start mass producing them.

Gordon Moore, a former employee of William Shockley, set up a company called Fairchild which took the integrated circuit and created the first microprocessor.

Moore, who is now chairman emeritus of Intel Corporation, said: "What we did at Fairchild was develop the technology to make these in quantities so that we could make reproducible transistors batch after batch and sell them at reasonable prices, reasonable prices in those days being a few to several dollars per transistor.

"To me that was a major contribution to the development of the industry, because the real advantage of integrated circuits has proven to be the decrease in the cost of electronics, more that than the increase speed or decreased power or anything else.

"Today you can buy a transistor for one 10 millionth of the price of transistors that we sold in the late 1950s."

So will the transistor go down in history as the most important invention this century, or perhaps even the most important invention ever?

Neil Johanneson said: "Certainly the transistor was one of those moments that created the later part of the 20th century, but whether or not it will be overwhelmed by something that comes up in perhaps 10 or 20 years' time no-one could say."

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Lucent Technologies - 50 years of the transistor

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