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Alloy Junction Transistors From RCA

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Inside two RCA alloy junction transistors from the 1950s. The smaller one is a 40V/50mA pnp and the larger is a 40V/250mA, hence the thicker wires for lower loss at the higher current. The metal connecting the base is also larger to provide better heat dissipation. The base is a thin cut slice of pure n-type germanium which has indium pellets alloyed to each side creating the pnp junctions.  There was viscous white goo inside the cases which was difficult to remove.

Texas Instruments Germanium Grown Junction Transistor

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TI introduced the 900 series silicon transistors in 1954 but they continued to produce germanium transistors. The germanium grown junction 2N172 was introduced in 1956, adding to their transistor portfolio for radios. TI and IDEA introduced the first all transistor radio (Regency TR-1) in 1954. TI started transistor development in Lemmon Avenue in Dallas and in 1958 moved to a 300 acre site at North Central Expressway. The Semiconductor building was the first building on the campus. The building is still there (although modified) and is now a Raytheon building following the acquisition of TI's defense business in 1997.  Working transistor, hfe=23, Vf=183mV, fairly low gain.

Sylvania Germanium Transistors

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Germanium transistors from 1955. In the early 1950s Sylvania established transistor and diode manufacturing at their tube (valve) facility in Emporium PA. Manufacturing was transferred to the Electronics Divsions in Woburn Mass. In 1957 it was divided into two new organizations, the Semiconductor Division and Special Tube Operations. Skyworks, one of the current world leaders in RF components for smartphones has its roots in Sylvania, Woburn.

RCA Germanium Transistors for Audio

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The 2N109 was the first widely used 'hobbyist' RCA transistor and was used in AM receiver and preamplifier circuits. RCA originally established transistor development and manufacturing at Harrison NJ, then built a dedicated solid state operation at Somerville NJ in 1955.

SACD Passed me by, Until Now (Updated)

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Back in the day I knew about DSD (Direct Stream Digital) and SACD (Super Audio CD) but it passed me by. I was still in Burr-Brown when DSD data converter ICs were first being developed by the design team in Japan, and I'm sure I was present when they were being presented at seminars to customers, but at the time I had little or no interest in diving in personally. Burr-Brown invested heavily in designing ICs for the upcoming market demand, but as history tells us, it didn't become mainstream. Certainly not in the US, less so in Europe, but in Japan there was always demand. Philips and Sony originally developed SACD as the high end next generation of CD, and certainly the format was capable of encoding a significantly higher level of audio information on the platform. DSD was a delta-sigma bitstream format that sampled 1-bit at 2.8MHz. Philips Semiconductors (amongst others) developed an SACD processor and Burr-Brown (amongst others) developed DSD Digital to Analog converters. L

Burr-Brown 12-Bit Digital to Analog Converters From the 1980s

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The photo above shows a hybrid technology 12-bit D/A Converter from Burr-Brown Corporation. By 1986 this was replaced by a monolithic i.e. single chip design. Under the metal lid is a ceramic substrate based multi-chip module. See below for examples of the technology. DAC85 is the model number. The 1st C is the operating temp range (0 to 70C). CBI is complementary bipolar inputs and V is the voltage output version. 12-bit DACs from Burr-Brown were used primarily in industrial applications like automation and factory control. If you only know DACs for digital audio, then 12 bit may seem a low resolution, but parameters that were most important for high end industrial use would not be relevant for audio. These DACs were very precise.

Burr-Brown Operational Amplifiers

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Burr-Brown Research Corporation introduced the first solid state modular op amp in 1962. It was a circuit board based device with discrete transistors, resistors, capacitors etc in a fully tested potted module. The 1510 example potted module op amp in the image is date coded 1971.  Fairchild Semiconductor had introduced monolithic bipolar op amps in the 1960s but they were low performance.  There was no ability to trim parameters on-chip, but within the Burr-Brown modules it was possible.  It wasn't until the likes of Burr-Brown and Precision Monolithics developed on-chip thin film laser trimming that precision analog ICs were introduced. The Burr-Brown OPA134 OpAmp on top for size comparison is from 1996.

The First Commercially Available Transistor in Large Quantities

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This is a Raytheon Germanium Alloy Junction transistor from the very early 1950s. The CK718 was the first transistor manufactured in large quantities for commercial applications.  The socket is for a mini vacuum tube. Raytheon replaced tubes with transistors in hearing aids, one of the first applications for solid state transistors. Raytheon was quick off the mark in the early development of transistors and were first to market with the CK703 point contact transistor in 1948. The CK722 alloy junction transistor was the first widely available transistor and opened up the technology to hobbyists. CK722s were originally lower grade CK718 test rejects. In the background is part of the original Bell Labs internal voting form for the name of the new device they had invented. This is a high gain device, Hfe=176, Vf=189mV.

Point Contact Transistors

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The first transistors developed by Bell Labs were Point Contact versions, created using an extension of diode manufacturing, which was a further refinement of diodes in 'cat's whisker' radios.  This 2N110 is a Western Electric Point Contact transistor from the 1950s. Point Contact transistors were difficult to manufacture and were superseded by grown junction, then alloy junction versions.  Western Electric continued to manufacture them longer than any other company since they were designed into telephone Central Office systems on a large scale. In the background is a page from Walter Brattain's logbook describing the first point contact transistor. A little bit more information in this previous post :  https://spingalhistory.blogspot.com/2017/02/bell-labs-point-contact-transistor.html  

Transitron Electronic Corporation

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2N543 Silicon NPN Transistors From 1965 / Zener Diode From the Late 1950s Founded in 1952 by the Bakalar brothers, David and Leo, Transitron became the world's largest and most highly valued semiconductor company in the late 1950s. Although it took a planar process license from Fairchild in the early 1960s it never regained its pre-eminent position. Transitron started in Melrose Mass and grew very quickly, moving to an old mill in Wakefield. At its peak it employed more than 10,000 people.  2N343 Silicon Grown Junction Transistors From 1961 In its early years the Bakalars were very active in recruiting top engineers from Europe. They would hold recruitment roadshows in major capital cities. A number of these recruits subsequently became pioneers in other semiconductor companies. Not just from Transitron, but much of the top talent migrated West to seek their fortunes. The established East Coast companies didn't adapt and provide stock options or other incentives. Transistron 2N