Dec 232016
 

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On this date in 1947 the transistor was first demonstrated at Bell Laboratories. The invention of the transistor is one of the great milestones in electronics, completely revolutionizing the field from radios to calculators and computers. The transistor not only miniaturized electronic circuits but also saved power and dramatically reduced the production of heat.

The forerunner of the transistor was the thermionic triode, a vacuum tube invented in 1907 which enabled amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a lot of power. Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode. However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor materials was still decades away, Lilienfeld’s solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such a device had been built.

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From November 17, 1947 to December 23, 1947, John Bardeen and Walter Brattain at AT&T’s Bell Labs in the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Group leader William Shockley saw the potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors. The term transistor was coined by John R. Pierce as a contraction of the term transresistance. Shockley had proposed that Bell Labs’ first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley’s proposal because the idea of a field-effect transistor that used an electric field as a “grid” was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor. In acknowledgement of this accomplishment, Shockley, Bardeen, and Brattain were jointly awarded the 1956 Nobel Prize in Physics “for their researches on semiconductors and their discovery of the transistor effect”.

In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II. Using this knowledge, he began researching the phenomenon of “interference” in 1947. By June 1948, witnessing currents flowing through point-contacts, Mataré produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs’ scientists had already invented the transistor before them, the company rushed to get its “transistron” into production for use in France’s telephone network.

The first high-frequency transistor was the surface-barrier germanium transistor developed by Philco in 1953, capable of operating up to 60 MHz. These were made by etching depressions into an N-type germanium base from both sides with jets of Indium(III) sulfate until it was a few ten-thousandths of an inch thick. Indium electroplated into the depressions formed the collector and emitter.

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The first “prototype” pocket transistor radio was shown by INTERMETALL (a company founded by Herbert Mataré in 1952) at the Internationale Funkausstellung Düsseldorf between August 29 and September 9, 1953.  I discovered transistor radios in around 1964 when they started becoming popular with teenagers in South Australia but I did not get one until 1965 after I had moved to England. Back then pop music was not played on the BBC but there were pirate stations such as Radio Caroline and Radio London that I listened to when I could get a signal, along with the ever popular Radio Luxembourg in the evenings.

For a seasonal treat here’s Alan Sherman’s 12 Days of Christmas parody that mocks Japanese transistor radios:

Radio cooking shows were very popular of course, and famous chefs on television often got their start on radio.  Here’s a well known Christmas radio recipe (HINT: the bottle of Irish whiskey in the ingredient list is very important).