TRANSISTOR MUSEUM HISTORIC GERMANIUM COMPUTER TRANSISTORS CBS HYTRON

Size: px

Start display at page:

Download "TRANSISTOR MUSEUM HISTORIC GERMANIUM COMPUTER TRANSISTORS CBS HYTRON"

Shon Watson
6 years ago
Views:

CBS HYTRON 2N385: Sylvania was the initial developer of the 2N385 and registered this device with the JEDEC industry organization in July 1957, with the following description: The Sylvania Type 2N385

This type of transistor is an example of the broad range of switching devices developed in the mid to late 1950s by many semiconductor companies to address the expanding digital computer market.

The 2N385 transistor shown above left was developed by CBS around 1960 to compete with the Sylvania device. CBS was a primary second source manufacturer of the 2N385.

1 CBS HYTRON 2N385: Sylvania was the initial developer of the 2N385 and registered this device with the JEDEC industry organization in July 1957, with the following description: The Sylvania Type 2N385 is a hermetically sealed NPN germanium alloy junction transistor. It is designed especially for computer applications where a moderate transistor gain is required. This type of transistor is an example of the broad range of switching devices developed in the mid to late 1950s by many semiconductor companies to address the expanding digital computer market. And, as was often true for devices which were commercially successful, competing companies would produce their own versions of these transistors. The 2N385 transistor shown above left was developed by CBS around 1960 to compete with the Sylvania device. CBS was a primary second source manufacturer of the 2N385. 2N438/39/40: This line of computer transistors was registered with JEDEC by CBS in December 1957 and was successfully manufactured by CBS for several years and was also second-sourced by General Transistor, Raytheon and Sylvania. The 2N438/39/40 devices have similar characteristics, except for switching speed the 2N438 has a cut-off frequency between mc and the 2N440 can exceed 10 mc. These devices were all manufactured on a common production line and then individually tested to confirm performance and final device type labeling. Note the differences in the case styles between the 2N385 and the 2N438/39/40 transistors shown above. The 2N385 illustrates the more modern TO-5 case style, including the small case tab for lead identification. The CBS 2N438/39/40 case is an earlier style, identified as TO-9, which was common for mid-1950s transistors, prior to industry standardization in the 1960s on the TO-5. Also note the differences in the header construction between these transistor types there was little standardization in transistor header construction and materials in the 1950s. Historic Germanium Computer Transistors Research and Collecting Kit Page 1

CBS HYTRON Shown at upper left is the cover of a 1957 CBS Hytron brochure promoting their new 2N438, 2N439 and 2N440 line of NPN high frequency transistors.

of these CBS types from a 1961 Radio-Electronic Master Catalog. These devices were expensive, with the $5.78 2N440 price equivalent to over $45 in 2014 prices.

audio types for hearing aids, NPN alloy switching types and PNP alloy power transistors. CBS exited the transistor manufacturing business in 1962.

2 CBS HYTRON Shown at upper left is the cover of a 1957 CBS Hytron brochure promoting their new 2N438, 2N439 and 2N440 line of NPN high frequency transistors. Two inserts from this brochure are shown above, left with a suggested flip-flop circuit and right with a description of the suitability of these devices for computer use. CBS offered a broad range of NPN germanium transistors for computer use beginning in the late 1950s, and the price data shown above right is a partial listing of these CBS types from a 1961 Radio-Electronic Master Catalog. These devices were expensive, with the $5.78 2N440 price equivalent to over $45 in 2014 prices. CBS entered the transistor manufacturing business in the early 1950s, and produced a variety of types, including early point contact types, PNP alloy junction audio types for hearing aids, NPN alloy switching types and PNP alloy power transistors. CBS exited the transistor manufacturing business in For a few short years in the 1950s and early 1960s, CBS was a competitive manufacturer of germanium computer transistors, and remaining devices well represent semiconductor technology from the first decade of computer transistor development. Historic Germanium Computer Transistors Research and Collecting Kit Page 2

CBS HYTRON Engineering Sample Requests (1232/LT-5007 and 7258/LT-5144): The manufacturing processes used for the production of germanium transistors in the 1950s were not well understand, resulting

Shown above are two types of CBS germanium NPN alloy junction transistors which were labeled with proprietary numbers and which represent devices produced to meet customer sales requests for

3 CBS HYTRON Engineering Sample Requests (1232/LT-5007 and 7258/LT-5144): The manufacturing processes used for the production of germanium transistors in the 1950s were not well understand, resulting in highly variable performance, and it was common for companies to establish production lines based on a specific technology and then use the test and sort method to identify and label transistors based on tested performance. It was also common for transistor manufacturers to use a proprietary in-house numbering/identification scheme for types which did not perform according to the more standard JEDEC 2N categories. Shown above are two types of CBS germanium NPN alloy junction transistors which were labeled with proprietary numbers and which represent devices produced to meet customer sales requests for performance characteristics that couldn t be met with the existing CBS 2N types. The unit at left is from a production run to fill Engineering Sample Request Order #1232 in June 1961, also identified on the device bulk packaging as CBS type LT The unit at right is from a production run to fill Engineering Sample Request Order #7258 in March 1961, also identified on the bulk device packaging as CBS type LT (Note: the 210 stamped on this transistor is the EIA code for CBS and the 113 is the date code, week ). CBS used the in-house LT transistor identification code on quite a few 1950s transistor types and sold these, either as part of a specific Sales Order, or as listed in industry catalogs if the type was in demand. A similar approach to transistor identification codes was used by other early germanium transistor manufacturers, including the 4JD sequence for General Electric. The meaning of the LT identification used by CBS isn t documented but may be an acronym for Lowell Transistor, since the CBS Semiconductor Operations facility was located in Lowell Massachusetts. There is no documentation to identify the customers for the above shown Engineering Sample Requests, but CBS did supply Engineering Samples in this same timeframe to Burroughs and NCR. These are very rare germanium computer transistors with a unique historical background, with very few surviving examples. Historic Germanium Computer Transistors Research and Collecting Kit Page 3

CBS HYTRON The Last CBS Transistors: Shown at left is a section of a CBS ad in the January 1961 Proceedings of the IRE announcing the availability from CBS of one of the leading germanium computer

This type had been invented and introduced by Philco several years earlier and the very high switching speed achieved by the Philco MADT technology ensured that the 2N501/501A would be widely used in

4 CBS HYTRON The Last CBS Transistors: Shown at left is a section of a CBS ad in the January 1961 Proceedings of the IRE announcing the availability from CBS of one of the leading germanium computer transistor types of the time, the 2N501/501A. This type had been invented and introduced by Philco several years earlier and the very high switching speed achieved by the Philco MADT technology ensured that the 2N501/501A would be widely used in digital computers. Several transistor manufacturers, including Sprague, General Instrument and CBS, rushed to introduce their own versions of this popular device. By the late 1950s, CBS had developed a broad range of germanium transistor types, and was best known for its PNP power devices and NPN computer switching types the top image in the scan above is excerpted from an early 1960s CBS brochure and illustrates the range of transistor types available. CBS exited the transistor manufacturing business in 1962, after competing for over a decade with high performing and historically important germanium devices. Raytheon took over the CBS power transistor business and continued to manufacture these devices for a few years, but CBS computer transistors all but vanished from the market in Historic Germanium Computer Transistors Research and Collecting Kit Page 4

GENERAL INSTRUMENT/GENERAL TRANSISTOR JAN 2N1305: The 2N1302 to 2N1309 series of transistors was originally developed by Texas Instruments in the late 1950s to provide a complementary range of

This series of transistors was very successful and was used extensively throughout the 1960s and 1970s in commercial and military computer applications.

5 GENERAL INSTRUMENT/GENERAL TRANSISTOR JAN 2N1305: The 2N1302 to 2N1309 series of transistors was originally developed by Texas Instruments in the late 1950s to provide a complementary range of NPN/PNP high-frequency transistors for computer and switching applications. The 2N1305 is the PNP complement to the NPN 2N1304 transistor, both of which will operate up to a cutoff frequency of 5MC. This series of transistors was very successful and was used extensively throughout the 1960s and 1970s in commercial and military computer applications. Several transistor manufacturers, including General Instrument, second-sourced this popular line of computer transistors, and the 2N1305s shown above are devices from GI. These units are marked as JAN 2N1305, which means this transistor type was manufactured and tested to meet the Joint Army-Navy specifications, and thus was qualified for military use. Note also the difference in the color of the glass/epoxy header material between the two leftmost units above. This color difference commonly occurred in germanium transistors from this timeframe, and it is unclear as to the significance, if any, of these differences. Finally, note the manufacturer ID GIT for General Instrument Transistor. U.S. Army 2N425: The 2N425/6/7/8 line of computer transistors was registered with JEDEC by Raytheon in 1957 and was a very successful product line throughout the 1950s and 1960s. Many other transistor companies second-sourced these transistors, including General Instrument, as shown above right. Raytheon had originally developed these transistors under contract from the Army Signal Corps, and large quantities were later manufactured and tested to meet specific Army specifications. As shown above, these transistors were labelled U.S. Army. The specific GI units shown have date code 1966 week 46, and appear somewhat crudely manufactured, especially when compared with the more refined case finish and consistency of the GI 2N1305 transistors at upper left. Also, the GI 2N425 units are poorly stamped, and the type info is difficult to identify without magnification. The 2N425 type was used extensively in early computers, including the Univac LARC from Historic Germanium Computer Transistors Research and Collecting Kit Page 5

GENERAL INSTRUMENT/GENERAL TRANSISTOR General Instrument Germanium Computer Transistors: Above are sections of an ad from the January 1961 Proceedings of the IRE, identifying some of the types of

6 GENERAL INSTRUMENT/GENERAL TRANSISTOR General Instrument Germanium Computer Transistors: Above are sections of an ad from the January 1961 Proceedings of the IRE, identifying some of the types of germanium computer transistors available at that time from the General Instrument division of the General Instrument Corporation. There are a couple of historically important aspects of early computer transistor history reflected in this ad: (1) General Instrument (GI) had not been known or documented as a manufacturer of transistors in the 1950s, and this ad, from early 1961, is likely one of the first industry ads from GI indicating availability of transistors and (2) GI had acquired another transistor company, General Transistor, in 1960 and this acquisition was the primary approach used by GI to become a major semiconductor company. Note the reference to General Transistor in the ad, both in the text below the graph, and also in the company logos at the bottom of the ad GT becomes GI. General Instrument used a somewhat ambiguous identification stamp on their transistors from the early 1960s, so that the stamp could be read as either a stylized GT or GI. General Transistor had been an early leader in high speed germanium computer transistors from the mid-1950, and GI was surely interested in maintaining this business after the 1960 acquisition note the focus of the ad on computer transistors. Throughout the 1960s, GI established a solid reputation as a second-source supplier of germanium transistors, primarily for military and industrial applications and, by 1966, sold a broad range of semiconductors including germanium and silicon transistors and diodes, field effect transistors, rectifiers, thyristors, photosensors and integrated circuits. Historic Germanium Computer Transistors Research and Collecting Kit Page 6

GENERAL INSTRUMENT/GENERAL TRANSISTOR 2N501: The 2N501 transistor type was registered by Philco with JEDEC in 1959, with the following description: The 2N501 is a hermetically sealed Micro Alloy

7 GENERAL INSTRUMENT/GENERAL TRANSISTOR 2N501: The 2N501 transistor type was registered by Philco with JEDEC in 1959, with the following description: The 2N501 is a hermetically sealed Micro Alloy Diffused-base Transistor (MADT) specifically designed for very high speed switching applications. Reliable operation of the 2N501 in switching circuits has been achieved at speeds in excess of 20 megacycles. Philco had established an early 1950s leadership position in high speed transistor design with the famous SBT (Surface Barrier Technology), and the MADT was an extension of this original type. Because of the excellent high speed performance, the 2N501 and related types were sold in large quantities throughout the 1960s. General Instrument was one of several second-source suppliers of the 2N501, and the GI units shown at upper left are examples from 1964 week 16. Note the bullet-shaped case style for the 2N501 - this was originally developed by Philco for the earlier SBT types and was registered as JEDEC case specification TO-30. The 2N501 was used in many historic computers, including the MIT TX-2 and the Univac LARC. 2N519A: General Transistor Corporation was a leading supplier of germanium computer transistors, beginning in the mid-1950s until 1960, when the company was acquired by General Instrument. GT registered the original 2N519 with JEDEC in 1958 with specifications as a medium speed switching transistor. The 2N519A was registered at a later date as an improved version of the 2N519. General Transistor devices typically used the unique TO-9 case style, which was common in the 1950s prior to the standardization by most manufacturers to the JEDEC TO-5. The 2N519A transistors at above right are TO-9, date code 1958 week 52, identified with a small GT stamp. The 2N519A was a rugged industrial type transistor, although the low switching speed of.5 megacycles limited in use in higher speed computers. The 2N519A did find use in analog computer applications, as the basis for operational amplifier design. For example, patents and describe op amp circuits for the 2N519A. Historic Germanium Computer Transistors Research and Collecting Kit Page 7

GENERAL INSTRUMENT/GENERAL TRANSISTOR General Transistor and Early Germanium Computer Transistors: General Transistor Corporation was an early leader in the design and production of germanium

The scan shown above is a partial excerpt of a GT ad from the February 20, 1959 edition of Electronics magazine.

Gold bonded diodes and an early silicon transistor type are also noted.

8 GENERAL INSTRUMENT/GENERAL TRANSISTOR General Transistor and Early Germanium Computer Transistors: General Transistor Corporation was an early leader in the design and production of germanium transistors. GT transistors were used extensively in 1950s commercial products including radios and computers. The scan shown above is a partial excerpt of a GT ad from the February 20, 1959 edition of Electronics magazine. In addition to the high speed and general purpose transistors mentioned above, other GT germanium transistor types highlighted in this ad include bilateral, drift, high voltage and phototransistors. Gold bonded diodes and an early silicon transistor type are also noted. General Transistor Corporation was a short-lived company (1954 to 1960) but was very influential in the early days of transistorized computers - GT computer transistors were highly reliable and were capable of high speed performance. GT transistors were used in large quantities by Univac, CDC and many other computer companies. For example, the circuit board at left is a digital computer flip-flop module, which was manufactured by 3C (Computer Control Company) this module uses three GT793 transistors, date coded 1958 week 44. General Transistor used both the standard 2N identification system for its devices as well as a proprietary GT numbering system. These transistors use the distinctive and easily identifiable TO-9 case style common to many GT computer transistors. General Transistor was acquired by General Instrument Corp in 1960, which continued to manufacture the successful GT computer transistor types. At left are examples of the 1950s GT transistor packaging (note the data processing design graphics) and a 1960s GI transistor package. Historic Germanium Computer Transistors Research and Collecting Kit Page 8

TRANSISTOR MUSEUM HISTORIC GERMANIUM COMPUTER TRANSISTORS CBS HYTRON

TRANSISTOR MUSEUM HISTORIC GERMANIUM COMPUTER TRANSISTORS CBS HYTRON Early CBS Transistors: Probably best known for its long-lived radio and television networks, the Columbia Broadcasting System was also a manufacturer of electron tubes and semiconductors. The CBS Hytron