GEC logo

The General Electric Company Limited of England (no connection with General Electric in the USA) was perhaps the greatest of those classic British electrical manufacturing companies that made everything from heavy plant down to miniature components. The long and complex evolution of the company is documented in several sites on the Web, from its pre-history in the 1880's to its near-collapse and renaming as Marconi Corporation in 2004, and its final purchase by Ericsson.

In the 1950's and 1960's GEC played a major role in British semiconductor research and development, which was not far behind the Americans. However, information about this period of their industrial history is scarce. As with Mullard, much more information can be found about GEC's valves/tubes than about their transistors. The most informative source that I have found is a book in Google Book Search, "The GEC Research Laboratories, 1919-1984" by Robert Clayton and Joan Algar. This explains that their research laboratory was based in Wembley, North London, and after an initial period, their germanium transistor manufacturing plant was established in Hazel Grove (Stockport) in 1956. In 1961, GEC merged its semiconductor interests with those of its main competitor in the UK, Mullard Ltd., to form a joint venture called Associated Semiconductor Manufacturers (ASM). Devices were marketed through Mullard, and so GEC devices can be found bearing the Mullard name, examples can be seen below. ASM went on to develop silicon transistors, but by then they were using standardised type number prefixes, and so these were never marketed in the traditional GEC type ranges.

GEC's main semiconductor product lines were the GET series of germanium transistors and the GEX and SX series of germanium and silicon diodes. Their experimental types and development samples used the prefix EW, which stands for 'experimental Wembley'. These are particularly interesting and desirable to me. Their devices usually bear the GEC logo, the type number in capitals e.g. GET103, and often the two-letter date code employed by the UK military CV series.

GEC were active in the early development of transistor radios. They first published a circuit in 1951, using five point-contact transistors. A slightly more practical set of circuits was published in 1954, again using point-contact transistors. One of these historic radios has been reconstructed by a correspondent, Henry Irwin. To my knowledge, this is the only working point-contact transistor radio in the world.

I do not possess all the transistors below, in fact I am seeking examples and data for many of them. It is noted in the text where I am seeking examples of any particular type: if you have some for sale or exchange, please Conversely, I am happy to help anyone looking for information on these devices. I have an extensive collection of original data sheets and books, and can provide characteristic data on almost all GET series types.

GET1 transistor

The first transistors made by GEC were the GET1 and GET2 point-contact switching types, for which I have data sheets dated 1953 and 1954, although GEC certainly had experimental versions several years before that. These transistors are characteristic of early point-contact types in that the base lead emerges from the opposite end of the cylindrical can from the emitter and collector. This is because the base wire is attached to one side of the germanium die, and the collector and emitter point-contacts press upon the other. Both types use a squat cylindrical aluminium can, with what looks like rubber end caps through which the wires emerge. Early versions have the GEC logo and the part number engraved in the metal; later examples have a shrink-fit yellow plastic band with that infomation printed upon it. Specimens in original condition come in a small sealed polyethylene packet containing a printed card bearing the words "CRYSTAL TRIODE" and various details.

EW51 transistor

The above two GET types were the only point-contact transistors sold commercially by GEC, although I doubt that they were ever offered to anyone other than government research institutions like Harwell Laboratories. However, a small number of point-contact transistors in the EW experimental series are mentioned in the literature. One is the EW51, another switching transistor. I have some examples in original packets as shown, which contain a card printed "POINT CONTACT GERMANIUM TRIODE". I have another loose with its card, which is printed "CRYSTAL VALVE" and has the part number crudely rubber-stamped on it.

I am seeking examples of any EW series device. I also wish to buy original data sheets for any of these devices. If you have some, please

EW58 transistor

In 1955 GEC announced its first junction transistors, EW53 and EW58, in a copper can with a black plastic surface and a small paper label fixed on it. Both came in several versions distinguished by a suffix eg the EW58/2 shown. All were germanium low-power AF types. This is the last usage of the term 'CRYSTAL VALVE'.

GET3 transistor

In 1956 GEC announced the GET3, GET4 and GET6, all germanium PNP low-power types that are presumably production versions of the EW53 and EW58 devices. However, some used this unusual crudely black-painted can with three longitudinal grooves in it. By this time GEC was using the term 'transistor'.

EW80 transistor

I was able to buy some EW80 devices (now out-of-stock) from the amazing Web site They have no data on these but my research reveals that in April 1958 the UK magazine "Wireless World" mentioned them briefly as "effectively a high-voltage version of type GET4".

I am seeking original data on this type. If you know where I can find it, please

GET5 transistor

Also in 1956, GEC announced the GET5, a medium-power AF type. This seems to have used the same can as the GET3, GET4 and GET6, but presumably unpainted, and fitted into a 1-inch square black anodised aluminium heatsink, perhaps using the grooves mentioned above to locate it. GEC made a good number of types in this package, which is one of my all-time favourite transistor shapes. The date code NC on this example stands for March 1957.

I am seeking examples of the type GET10, which had the same size and shape, if you know where I can find any, please

EW70 transistor

Again there was a prototype device, the EW70, although the only reference to it that I have found is in Wireless World in 1957. I know from an image in that magazine that the first examples had a more primitive heatsink made from bent sheet metal. Some of the GET5's may also have had this form.

I am seeking original data on EW70, and examples of any GEC device with such a primitive heatsink. If you know where I can find any, please

GET7 transistor

In 1957 GEC produced their first true AF power transistors, the GET7 to GET9, in a package that looks like a protype TO-3, but taller with three leads rather than two pins, and without the solid base plate. These types were released about a year after Mullard had issued their first power AF device, the OC16.

In 1959 GEC released three more power AF types in the same package, the GET571 to 573.

I am seeking examples of the GET9. I also wish to buy original data sheets for any of these three devices. I am unaware of any EW prototype using this can, and would be extremely interested in any that may exist. I'm also looking for CV series equivalents of these. If you know where I can find any of these things, please

GET103 transistors

In about 1958, GEC decided to re-order the leads on their transistors, presumably to make them compatible with other manufacturers. They distinguished the 'new' types from their originals by adding 100 to the part number. The image shows GET103 to GET106. However, I have a number of GET102's which are junction types in the usual red-sleeved can, and are most certainly not rewired GET2's, that being a point-contact transistor. NB the GET105 is branded 'Mullard', which means that it dates from after the creation of ASM, as shown by the date code UH, which means August 1963.

I possess one specimen of a Mullard-branded GET118, in an unusual white sleeve. I can find no data on it. If you know about it, please

GET873 transistor

The GET871 to GET875 types, from 1959 onwards, usually found in blue plastic sleeves, were IF/RF types commonly used as switches and amplifiers. These were used in a number of British transistor computers.

GET691 transistor GET671 transistor

The GET691 to GET693 types, in an unusual green sleeve, formed a short-lived series of germanium PNP IF types from about 1960. They were not commercially successful and were planned to be replaced in 1962 by similar types in more modern TO5-type cans, the GET671 to GET673. However, in 1961 a "joint venture" was formed called Associated Semiconductor Manufacturers Ltd. (ASM), owned two-thirds by Philips and one-third by GEC. In effect the GEC semiconductor lines were taken over by Mullard, and although GEC types continued for some years, they started to be branded Mullard, and eventually disappeared. The GET 67x series was never made available commercially.

I am seeking examples of GET693, GET672 and GET673 transistors. If you know where I can find any of these things, please

GET88x transistor

The GET88x range of devices from 1962 were a colourful set of high-frequency types in proto-TO-5 cans, intended for various applications - oscillators, switches, and RF amplifiers. These were made late in the span of GEC's semiconductor production, and Mullard-branded versions are even more common than GEC examples.

S1 transistor

This GEC S1 transistor, and similar S3, S5, S6 and S7 in my possession, are devices for which I have no data. I also have a few S1 in the original black-painted can used by the earliest GEC junction types, such as GET3. One might guess that the part number suggests that these were GEC silicon transistors, but measurements show that is not so: they are germanium.

I have learned that two S1s were used as output transistors in the Baird Wondergram miniature record player (sold in the USA under Emerson) from 1960. The transistors can be seen clearly on this Russian site and the schematic is available on the Radiomuseum site. Incidentally, the 'RF' printed on the transistors (and shown on the schematic) is the CV date code for June 1960, not an abbreviation for 'radio frequency'.

I am seeking examples of S2 and S4 transistors. I also wish to buy original data sheets for any of these devices. If you know where I can find any of these things, please

GEC diodes

Of course GEC made diodes too, both germanium (GEX prefix) and silicon (SX prefix) types, and an odd-looking bunch they were. From left to right, the image shows a GEX541 power rectifier, a GEX55/1 general purpose type, a GEX946 gold-bonded diode (in the normal GEC low-power transistor can, with one lead soldered to the top), an SX82 silicon Zener diode in a small copper cylindrical can, and lastly an SX632 silicon medium-power rectifier.

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