Production of semiconductors in the former Soviet Union started in about 1947, and like most countries the first devices were point-contact diodes used as detectors for radar. In the 1950's work moved on to point-contact transistors, and quickly on to junction types, and then silicon transistors. Understanding the manufacturers of USSR devices is tricky, although most examples do bear a logo, many of which are listed here. Moreover, in a communist country the means of production are controlled by the state. Most technology manufacturing facilities were designated by a number, for example 'Scientific Research Institute (SRI) Number 35'. Manufacture was initially kept secret and the first devices were used by the military. Sometimes devices have no manufacturer's logo, just a rhombus that denotes that they meet military quality standards.

Svetlana logo

The best known manufacturer is Svetlana, whose logo is shown on the right. This organisation, based in St.Petersburg, is one of the oldest manufacturers of vacuum tubes in the world, and still exists today. There are a number of others.

There is a superb site by Andrey Roubtsov on the Web that describes these early devices, transistors and diodes, although it does not seem to be being updated. It is in Russian and it uses html frames that confuse the various browser translation options. You can usually guess the frame address if you want to get a translated version. It contains links to data sheets for many of the early types and much of what I state below is derived from it.

There are lots of scans of old USSR semiconductor data books on the Web, in Russian of course. Most are in djvu format, which pdf readers can usually handle. Some of the earliest are:

Those do not contain 'modernised' МП types: for those, the earliest I have found is:

For diodes there is one comprehensive list:

Another good source of information is the Livejournal of Aleksei Pogorily, which has pages on early transistors and diodes. (Those two hyperlinks pass the content through Google translate to render it in English).

Another source of data are the US National Bureau of Standards books by Charles Marsden entitled 'TABULATION OF PUBLISHED DATA ON SOVIET ELECTRON DEVICES'. I have found several of these downloadable on the Web, dated from 1963 to 1976.

Most USSR transistor types had a number of suffixes (often many), for example П1А, П1Б, etc., denoting versions of the same basic device. Of course, all part numbers are written in the Cyrillic alphabet. The plethora of suffixes creates a bit of a problem for the completist collector!

I do not possess all the transistors described below, in fact I am seeking 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

USSR transistors (and I believe other components too) often bear military designations, indicating compliance with military specifications or quality control. The most common ones are a white star in a circle, or the letters ВП which may be printed immediately after the part number, or sometimes elsewhere on the device body. ВП stands for 'воинские подразделения' which translates as 'military units' or 'military mission' and is explained on this page of the Russian wikipedia. After translating and reading it I am still not completely clear what it means!


I have come across an interesting document on the Web: 'Translations on Eastern Europe Scientific Affairs No 569', dated 12 January 1978, which contains the article 'SEMICONDUCTOR DESIGNATION SYSTEMS DESCRIBED'. Amongst those of other countries, it describes the semiconductor numbering systems used by the Soviet Union.


wanted transistor

Research on transistors started in the USSR in about 1950, and various experimental point-contact transistors were made in several laboratories. In late 1953 a range of devices was released for domestic use at some level. Web pages variously number them as either КС1 to КС8 or ТС1 to ТС7. I have no information on how they were used, and I cannot find an image of any on the Web. Needless to say I would be very interested to obtain these for my collection, so if you can provide information or any example, please

Я был бы очень заинтересован, чтобы получить примеры любой из этих для моей коллекции. Если у вас есть для продажи или торговли / обмена, пожалуйста,


The first production transistors were germanium point-contact types С1 and С2 (Latin S1 and S2) which use a smallish cartridge case rather similar to those made in other countries. Apparently production started in 1953, but examples dated earlier than 1956 are very rare.

С1 exists with six suffixes: А, Б, В, Г, Д and Е. This С1А was made by NII number 35, which became NPP Pulsar and exists to this day.

I'm seeking examples of С1Б, С1В, С1Г, and С1Д. If you have any for sale or trade/exchange, please

С1А transistor

С2 exists with four suffixes: А, Б, В and Г. This С2А was also made by SRI 35 and I have another made by Moscow plant #382 (now OJSC 'Pluton').

I'm seeking examples of С2В and С2Г. If you have any for sale or trade/exchange, please

С2А transistor

These were followed by С3 and С4 (Latin S3 and S4) in a small green or black "top hat" outline with a pronounced flange. These are point-contact devices electrically identical to С1 and С2 respectively but in more modern encapsulation. They have the same sets of suffixes as the С1 and С2 respectively. According to www.155la3.ru these are rarer than the original С1 and С2.

S3YE transistor S3D transistor S3V transistor S3B transistor S3A transistor

My images show С3А in both black and green, and green С3Б, С3В, С3Д and С3Е. All were made by Moscow plant #382 (now OJSC 'Pluton'). С3 and С4 seem to be the only USSR transistors that have this bright green colour, although some early semiconductor diodes do too.

I am seeking an example of С3Г.

S4 transistor

I am seeking examples of С4. There is also evidence of the existence of a type С5, listed on a page from "Semiconductor triodes in radio circuits", 1958. That book primarily contains extracts from Western publications, but has a table of USSR devices at the end. I have not found a downloadable version on the Web. I have found no other evidence for the existence of С5, so it is problematic. The text next to it is 'Точечный импульсный' which translates as 'point-contact pulse'.

I would be extremely interested to obtain examples of С4 or С5. If you have any for sale or trade/exchange, please

Мне было бы очень интересно получить примеры С4 или С5. Если у вас есть для продажи или обмена, пожалуйста,

unknown transistor unknown transistor

I have this puzzling transistor. It is in its original envelope, with handwritten serial number N284 and part number apparently ССА although it is badly written. The device itself is unmarked. I have a similar envelope with handwritten serial number N182 and part number clearly С3А; again the transistor is unmarked. Is this a badly written '4' and it is a С4А?

If you know anything about this, please


The first junction transistors that the Soviet Union made were the germanium PNP types П1 and П2 (Latin P1 and P2) from Svetlana and possibly other manufacturers starting in 1955. They use a co-axial construction with the emitter and collector at opposite ends and the base connection in the middle. All are suffixed and several suffixes were used. They have metal ribbon leads and the part number and date of manufacture are often stamped into them. These part numbers look as though they conform to State Standard 5461-59 but in fact they precede it.

Prototype versions had different part numbers: КСВ1, КСВ2 etc., I would be very interested to obtain examples of these, if you know where I might get any, please

The П1 has eight suffixes, А to И (there is no suffix З as that has a special meaning). The images below show that I am still seeking П1Д and П1И.

Я хочу получить примеры П1Д и П1И. Если у вас есть что-то на продажу или обмен, пожалуйста

P1A transistor
P1B transistor
P1V transistor
P1G transistor
P1D transistor
P1YE transistor
P1ZH transistor
P1EE transistor
P2A and P2B transistors

The П2 has only two suffixes: П2А and П2Б, although early data books list it with no suffix. This image shows a П2А made by SRI-35 (now NPP 'Pulsar') with the part number and date V-59 stamped into the lead and a П2Б in its original paper envelope with characteristic data values, some handwritten. I have not yet translated these. It has the part number and date 6-56 printed on the body. This is a high-voltage type, allowing Vce up to 100 volts.


P3V transistor P3B transistor P3A transistor

Next in number is the П3 (Latin P3), also germanium PNP, made by Moscow plant #382 (now OJSC 'Pluton') from 1955 and similar in construction to the П1 and П2, but in a longer case with three disc-shaped fins of about 2cm diameter allowing greater power dissipation of up to 3 Watts. It has three suffixes: А, Б, В all shown here. This was the only device to use this outline.


Then comes the П4 (Latin P4), a 5 Amp germanium PNP power transistor in a cylindrical hat-shaped can about 3cm in diameter, produced from about 1957. It is painted black, and early examples have wire leads crimped onto the three pins whilst later ones have solder tags instead. Again this was the only device to use this outline. It always has a suffix: one of А to Д (5 values) plus two rarities described below.

P4A transistor
P4B transistor
P4V transistor
P4G transistor
P4D transistor

The above are all dated between 1958 and 1962. Later production added a further suffix Э (Latin 'E') that indicates the presence of an internal metal screen to protect the crystal during hot-welding of the case.

P4AE transistor
P4BE transistor
P4VE transistor
P4GE transistor
P4DE transistor

The П4 is often offered on eBay: the device was very long-lived, until the 1980s.

P4U transistor P4P transistor

There are two rare variants: П4П (Latin P4P) and П4У (Latin P4U). My images show one of the former dated May 1958 and one of the latter dated July 1958, both made by Moscow plant #382 (now OJSC 'Pluton'). Documentation on these is hard to find. If you know where I can find documentation for either type, please

P4BM transistor

In addition to the big hat-shaped П4, there is a smaller variant in a more modern case with a second suffix М. It has suffixes А to Д : shown on the right is П4БМ, latin P4BM, dated December 1963. It has no mounting holes, but its specification allows even higher collector current than the regular П4, so I suspect a clamping ring should be used. According to this page, in 1965 these were renamed П216 and П217 with various suffixes.

There is another very unusual variant of the П4 that I am seeking: the rare type МП4 in the regular large hat-shaped can. I don't know what the prefix М signifies. It has variants with suffixes А and Б at least. If you know where I might get an example of this, please

Я ищу примеры П4П и МП4. Если у вас есть для продажи или обмена, пожалуйста,


P5 old style transistors P5A transistor P5V transistor

The next type is the П5 (Latin P5), which apparently is a copy of the Mullard OC70 and OC71 germanium PNP types, to the extent that it originally had a similar glass case, but this caused problems and so it was changed to a smaller metal one. This is quite a small device intended for use in hearing aids, miniature radio receivers, etc. operating at low voltage (1-5 V). It always has a suffix, either А, Б, В, Г, or Д.

My images show old-style П5А, П5Б and П5В made in early 1958 by SRI-35 (now NPP 'Pulsar'), and then the newer-style П5А and П5В made in 1960 and 1961 by Novosibirsk plant 453 URTP.


P6G transistor P6V transistor P6D transistor P6A transistor

The П series carries on with germanium PNP type П6 (Latin P6) in a small black 'top hat'. This was developed in 1955 as a replacement for the unreliable П1, using a more advanced welded case. It always has a suffix, either А, Б, Д, В or Г. My images show a Svetlana П6А dated November 1958, a Svetlana П6Д dated December 1957, an unbranded П6В dated May 1957 and a Svetlana П6Г dated February 1958. However П6 did not exist for long, being itself replaced by П13-П15.

I am seeking an example of П6Б.


wanted transistor

П7 (Latin P7) is another 'miniature' type in the same case as П5. Pogorily says it was only produced for a short time and http://www.155la3.ru does not show it. It seems to be the first П-series device that did not have a suffix, so possibly it was the first to really conform to State Standard 5461-59. If you know about it or have any for sale or trade/exchange, please

Я был бы заинтересован, чтобы получить примеры любой из этих для моей коллекции. Если у вас есть для продажи или торговли / обмена, пожалуйста,


P8 transistor

The П series continues with П8 (Latin P8), which was originally a large PNP power transistor that became П201 (Latin P201). The part number П8 was re-used for a small NPN germanium low-power type. As in my image, dated 1962, this has no suffixes.

The logo appears similar to the Svetlana 'winged C' but with a central 'T' instead, however I am reliably informed that the manufacturer is Planeta in Novgorod. They later changed logo to a broken circle with a dot inside.

I am seeking examples of the early large П8. If you know where I can find any, please

Я ищу примеры раннего большого П8. Если вы знаете, где я могу найти, пожалуйста,


P9 transistor P9A transistor P10 transistor P10B transistor P11 transistor

П8 is followed by П9 to П11 (Latin P9 to P11) all NPN low-power germanium in the small black 'top hat'. These are complementary to П13 to П15А. П9 comes with no suffix and the suffix А (both shown), П10 has three versions: no suffix, suffix А and suffix Б and П11 has two versions: no suffix and suffix А.

I am seeking examples of П10А and П11А.

MP9A transistor MP10B transistor MP11 transistor

I believe that МП9А (latin MP9A) is the lowest-numbered of the 'modernised' МП range that use the cold-welded case: my one was made by Svetlana in 1964 and the МП10Б was made by Planeta in 1969. My МП11 is later. The images show how the cold-welded case differs from the previous 'top hats' : there is an obvious base cylinder with the weld flange partway up the body. However, as the images below show, some later P-series types were, anomalously, fabricated in the cold-welded case, and some in both outlines.

Oddly, it is harder to find contemporary data for the low-numbered МП types than the П types, but I have located "Transistors - Reference" by V.K.Labutin second edition dated 1967 which contains many of them. (The 1964 first edition of the book contains only a few П types). The 1967 edition starts with (there is no МП9):


P12 transistor

Then comes П12 (Latin P12) from about 1957, a germanium PNP IF/RF type, for which early examples use a largish elongated can of oval cross-section like early US types. Later versions use the modernised МП-style cold-welded can, as shown in my Svetlana example dated 1962. Probably because of this, there is no МП version of it. Labutin 1967 lists a suffix А version but this seems to be very rare.

wanted transistor

I wish to obtain an example of П12 in the oval can and any suffix А version. If you have any for sale or trade/exchange, please

Мне было бы интересно получить примеры раннего формы П12 для моей коллекции . Если у вас есть для продажи или торговли / обмена, пожалуйста,


This is followed by П13 to П15 (Latin P13 to P15) in the black tophat, low-power germanium PNP types. These are improved versions of the П6.

P13 transistor P13A transistor P13B transistor

As well as no suffix, П13 has suffixes А and Б, the latter denoting a low noise variety. There is also an odd П13К. My example without suffix is dated 1962. My П13А and П13Б were made by a manufacturer I'm unsure of: their logo is a horizontal transistor symbol. I suspect this is SRI-35 (now NPP 'Pulsar') but their logo originally had a vertical transistor.

I wish to obtain an example of П13К. If you have any for sale or trade/exchange, please

P14 transistor P14A transistor

As well as no suffix, П14 has suffixes А and Б, the latter denoting a low noise variety. My example without suffix made by Voronezh plant is dated 1962. The П14А was made in March 1963 by Planeta.

I wish to obtain examples of П14Б. If you have any for sale or trade/exchange, please

P15 transistor P15A transistor

As well as no suffix, П15 has suffix А. My example without suffix made by Voronezh plant is dated 1962. The П15А was made in Nov 1964 also by Voronezh plant and is qualified for military use as indicated by the designation ВП (latin VP) that follows the part number.

MP13 transistor MP14A transistor MP15 transistor

Here are some МП equivalents: a 1980 МП13 made by Bryansk ZPP (now 'Silicon'), a Svetlana МП14А dated October 1971 and an МП15 dated December 1963 from Planeta.


P16B transistor P16A transistor P16 transistor

They are followed in 1959 by П16 (Latin P16) also in the black tophat, a germanium PNP type intended for logic switching circuits of relatively low speed. My image shows one made at Voronezh plant in 1964 and ВП qualified. Variants are П16А and П16Б (both shown, the second also ВП qualified) from multiple manufacturers.

MP16A transistor

Here's a modernised МП16А.


P17 transistor

Oddly, the next pair in the series, П17 and П18 (latin P17 and P18), revert back to the early co-axial outline like П1. Pogorily lists both as having three variants: no suffix, А and suffix Б. He says they were short-lived and were replaced by П25 and П26. My image shows a Svetlana П17А. (It has the part number stamped into the metal ribbon leads; you can also see the date 11-59).

I wish to obtain examples of П17, П17Б, П18, П18А and П18Б. If you have any for sale or trade/exchange, please

Я хочу получить примеры П17, П17Б, П18, П18А и П18Б. Если у вас есть что-то на продажу или обмен, пожалуйста


wanted transistor

П19 (Latin P19) is, according to Pogorily, another rare type, like П12 but smaller. There are no images of it on the Web.

I wish to obtain an example of П19. If you have any for sale or trade/exchange, please

Я хочу получить пример П19. Если у вас есть для продажи или обмена / обмена, пожалуйста,


P21A transistor P20 transistor

П20 and П21 (Latin P20 and P21) are germanium PNP tophats again, supporting higher current than previous members of the series. Pogorily lists no-suffix plus suffixes for П20 from А to Д and for П21 from from А to Е. The image shows a П20 dated Dec 1963 and a П21А dated June 1965, both made by SRI-35 (now NPP 'Pulsar').

MP21G transistor MP20 transistor

Here are the modernised versions. Of course, they use the cold-welded encapsulation.


wanted transistor

П22 and П23 (Latin P22 and P23) were, according to Pogorily, not produced for very long. A web search produces no images of them. There appear to be no МП versions of them, so they probably use the modernised cold-welded can.

I wish to obtain examples of П22 and П23. If you have any for sale or trade/exchange, please

Я хочу получить примеры П22 и П23. Если у вас есть для продажи или обмена / обмена,


wanted transistor

П24 (Latin P24) is a rare miniature type like the П5 (Latin P5) above.

I wish to obtain an example of П24. If you have any for sale or trade/exchange, please

Я хочу получить пример П24. Если у вас есть для продажи или обмена / обмена, пожалуйста,


P25B transistor P25A transistor P25 transistor

П25 and П26 (Latin P25 and P26) are germanium PNP high-voltage transistors that were manufactured over a long period in the original 'top hat' case, as replacements for the П2. They both have no suffix and suffixes А and Б. My П25 and П25А were both made by Svetlana in November 1961, the П25Б by Svetlana in March 1962.

I wish to obtain an example of П26. If you have any for sale or trade/exchange, please

Я хочу получить пример П26. Если у вас есть для продажи или обмена / обмена, пожалуйста,

MP26A transistor MP25B transistor

Here's the modernised МП25Б and МП26А.


P27A transistor P28 transistor

П27 and П28 (Latin P27 and P28) are germanium PNP low-noise transistors for the input stages of AF amplifiers, apparently only produced in the 'modernised' cold-welded case. Why these were not called МП types is unknown to me, and there appear to be no МП versions. П27 has three versions: no suffix, suffix А and suffix Б while П28 has no suffixes. My П27А was made by Planeta in Sept 1972 and the П28 is a Planeta example from June 1972.


P30 transistor P29 transistor

П29 and П30 (Latin P29 and P30) are germanium PNP low-voltage mid-frequency transistors with increased performance for pulse circuits, made from about 1967 and 1973 respectively according to http://www.155la3.ru. П29 comes with no suffix and suffix А, П30 has no suffixes. My unbranded П29 is dated August 1973 and the Planeta П30 is from November 1973. My images show them in the 'modernised' cold-welded encapsulation, I don't believe they were produced in the older outline or as МП versions.


wanted transistor

П31 to П34 (Latin P31 to P34) were developed but not issued commercially. http://www.155la3.ru does not show them. П33 and П34 are symmetrical transistors. No modernised versions exist.

I wish to obtain examples of these. If you have any for sale or trade/exchange, please

Я хочу получить примеры этого. Если у вас есть для продажи или обмена,


P39B transistor

Types П35 to П39 (Latin P35 to P39) are somewhat enigmatic. Pogorily lists them in an aside rather than giving their details, which suggests that their production was unusual somehow. He says that П35 to П38А are 'similar to П8 to П11А' and П39 is 'similar to П13'. Marsden lists only the П39Б in the 1967 edition of his book, but in the 1970 edition he has П35, П36А, П37, П38, П39, and П39Б. However the 1971 edition has none of them. www.155la3.ru does not show them, and a Web search reveals no images of them.

I only have the П39Б shown on the left, made by SRI-35 (now NPP 'Pulsar') in December 1964. Is it a co-incidence that this is the only one listed by Marsden 1967?

I am seeking examples of П35 to П39, if you know where I can find any or you know more about these types, please

Я ищу примеры от П35 до П39, если вы знаете, где я могу найти какие-либо или вы знаете больше об этих типах,

MP38 transistor

There are modernised МП versions with all of these numbers, such as this МП38.


P40A+ transistor

П40 and П41 (Latin P40 and P41) were made from the mid-1960s and are, according to Marsden, 'similar to П14 to П15A' whereas www.155la3.ru states they are non-military versions of the П15 and shows the oldest ones in the older hot-welded 'top hat', plus ones which are in the later cold-welded can like my example of a П40А+ dated 9-73. (The plus signifies a tighter minimum gain control). These should really be named as МП types, and puzzlingly those do exist as I show just below. As well as no suffix, both have suffix letter А and the П40 exists with suffix Б.

I wish to obtain examples of both of these in the older 'top hat' outline. If you have any for sale or trade/exchange, please

Я хотел бы получить примеры того и другого в старом наброске «цилиндра». Если у вас есть для продажи или обмена,

MP41 transistor MP40A+ transistor

On the right I show a Planeta МП40А+ from July 1971 (older than my П40А+!) and an unused Svetlana МП41 dated September 1965. This latter seems to have been quite a popular type.


wanted P42 transistor

П42 (Latin P42) is a rare 'pulse' transistor made from about 1965, the non-military version of П16А. It is found in both outlines (hot- and cold-pressed), with no suffix and with suffixes А and Б.

I wish to obtain an example of П42. If you have any for sale or trade/exchange, please

Я хочу получить пример П42. Если у вас есть для продажи или обмена / обмена, пожалуйста,

MP42B transistor

There is also a modernised МП42. The image shows an unused Svetlana МП42Б dated April 1965.


The П series then proceeds in jumps through groups starting П101, П201, П301, П401, etc, each group containing different types of transistor as listed in the document described near the top of this page. Each group, although having 99 numbers in it, usually contains only a small number of transistor types that were actually manufactured.


P106 transistor P101 transistor

The П1nn group comprises the first range of Soviet silicon junction transistors, in theory П101 to П200 (latin P101 to P200), in 1956. Pogorily lists the following as having been made:

There are few suffixes: П101А, П101Б, П103А and П108А. The images show a Svetlana П101 and a SRI-35 (now NPP 'Pulsar') П106 both made in 1960 in the old hot-welded 'top hat' case. I am seeking П108 to П110.

MP103 transistor MP103 transistor

There are modernised versions of these, as this МП103 shows. There also exist МП111 to МП116, I show МП113 but I am unaware of the existence of previous П versions.


The П2nn group contains germanium PNP AF power transistors, made from 1958 until at least 1976, in several subgroups.

P201 transistor P201A transistor P202 transistor P203 transistor

The first subgroup is

These use an outline with a diamond-shaped flange, similar to TO-66 but with three pins out of the bottom. My leftmost image shows an early П201 dated February 1959 from the Moscow plant #382 (now OJSC 'Pluton'). Then my Voronezh П201А from September 1964 that has the qualifier ВП. Then a П202 dated December 1958 with a rather unclear logo but must be from the Moscow plant #382. The rightmost Voronezh П203, dated January 1964, has wires crimped onto the short pins emerging from the case like the previous types.

P203E transistor

Later versions were produced with a suffix Э : my image shows a Voronezh П203З dated 1966. As with П4 the Э denotes an internal screen to protect the germanium die during welding of the casing. By now, solder tags are crimped onto the pins rather than wires.

P203M transistor

Versions П201М to П203М with a 'modernised' cold-welded body were also produced (the image shows an example by Moscow plant #382 (now OJSC 'Pluton') dated 1963). This uses a clamping ring to hold it tight against a heatsink.

wanted transistor

The second subgroup comprises the enormous types:

I wish to obtain examples of any of these, and of their non-standard prototypes 320А, 320В and 320Г. If you have any for sale or trade/exchange, please

Я хочу получить образцы любого из них, а также их нестандартные прототипы 320А, 320В и 320Г. Если у вас есть какие-либо для продажи или обмена / обмена,

P210 transistor

The third subgroup comprises

These use a largish round outline but smaller than П207 and П208. My image shows a П210 dated November 1963 made by Photon in Tashkent.

wanted transistor

The next subgroup contains rare types: П211, П212, П212А in the same round outline.

P214G transistor

Then comes a subgroup comprising devices created from a re-organisation of the group П201М to П203М:

These use a modernised outline like my П203М above.

P216A transistor

The last, and largest, subgroup comprises devices created from a re-organisation of the П4xМ group:

These use a modernised outline like my П203М above. Some of them were very long-lived.


The П3nn group types also come in subgroups:

P306 transistor

Medium-power silicon PNP types in a mid-sized round can issued from about 1960:

  • П302, П303, П303А, П304, П306, П306А (П306 shown)

I am seeking 1960's versions of these, possibly painted black. The image shows a 1985 Voronezh example.

These were then re-issued as modernised types with an M suffix in a plastic TO220-style outline, and with a suffix M1 in a metal outline.

P307A transistor P309 transistor

Low-power silicon NPN planar devices:

  • П307, П307А, П307Б, П307В, П307Г, П308, П309

Early П307 to П309 come in a unique bell-shaped can like the П309 shown, made by SRI-35 (now NPP 'Pulsar') in August 1964. Later ones use the МП flanged can like this П307А, unbranded and made in July 1973. There are even modernised versions with an М suffix in a plastic case.

I wish to obtain an example of the П308 in the bell-shaped can. If you have any for sale or trade/exchange, please

П314 with suffixes A, B and C (?) and П322 are, according to Marsden 1963, germanium PNP types. Putting aside the bizarre suffixes, these would not belong in the group. I have not seen examples or images of them and am sceptical of their existence.


The largish П4nn group holds germanium PNP high-frequency transistors in a number of different packages. Pogorily lists П401 to П423.

P401 transistors

The subgroup П401 to П403 and П403А were the first Soviet alloy-diffused transistors, developed in 1956-1957. This image shows the П401 in both the original П-series small 'top hat' dated 1962 and the МП-series cold-welded case dated 1964. However, the type numbers were not changed to МП for the modernised devices.

P405A transistor

The П404 and П405 (both also with suffix А versions) in a tall oval can are listed in Marsden's book from 1963 as germanium PNP surface barrier transistors of 10 MHz and 30 MHz respectively. I believe them to be rare. My image is of a П405А made by SRI-35 (now NPP 'Pulsar') in May 1958.

P407 transistor

The П406 and П407 are high-frequency versions of П12. They originally came in a tall oval can but changed to the standard modernised МП outline. I don't believe that МП versions were made.

wanted transistor

I am seeking the П406 and П407 in the tall oval can

The П408 and П409 are obscure but may also have used a tall oval can. I am seeking those too.

P411A transistor

The bizarre-looking П410 and П411 (both also with suffix А versions) are coaxial-type microwave transistors capable of 200-400 MHz.

wanted transistor

The П412 and П413 use the same can as П405 and also come in a small 'cigar tube' outline.

P415 transistor P416B transistor

П414 and П415 from 1961 (plus suffixes А and Б) use the old 'top hat' outline, and later the modernised outline. Again, the type numbers were not changed to МП for the modernised devices. They were superseded by П416 (various suffixes, my image shows П416Б) in the МП outline.

P417 transistor

П417 uses a taller cold-welded can with three leads in a line. It too is a germanium PNP RF amplifier. There is a suffix А version.

P418G transistor

П418 is also a co-axial microwave type up to 400 MHz. It seems to have suffixes Г, Е and И.

Pogorily says there is a П419 but he cannot locate data about it.

P420 transistor P423 transistor

П420 to П423 (the last two also have suffix А) use the old 'top hat' outline, and later ones switch to the modernised outline. Again, the type numbers were not changed to МП for the modernised devices. This П420 was made by Riga ZPP (now 'Alpha') in Sept 1963 and the modernised П423 by Riga ZPP in June 1964.


P503 transistor P501A transistor

The П50n group types are silicon PNP low-power high-frequency, in two subgroups:

use the taller cold-welded can with three inline leads. My images show П501А and П503 both made by SRI-35 (now NPP 'Pulsar') in mid 1963.

are found in several outlines including a version of the normal cold-welded МП can but with four leads.


P606A transistor

The П60n group comprises germanium PNP high-power high-frequency 'pulse' transistors in two subgroups:

for these there is no documented reason for the extra suffix И (latin 'I'), but the Russian for 'impulse' is 'импульс'. My image shows a П602АИ made by Riga ZPP (now 'Alpha') in 1968.

P606A transistor

My image shows a П606А made by Riga ZPP in March 1966. www.155la3.ru describes two variants: 'I' with wire leads like mine and 'II' with pins.

Later USSR data books contain:


P702 transistor

П701 and П702 are high-power high-frequency NPN silicon transistors. They first appear in Marsden 1965 together with suffix А versions, and П701Б appears in Marsden 1971. www.155la3.ru does not list them.


313A transistor 316G transistor 1602B diode

Before the introduction of State Standard 5461-59, and to a lesser extent after it, a few USSR semiconductors were made that use a slightly different numbering system: simply a number (usually, but not always, 3xx) followed by a suffix. These may be prototypes of П-series types. Pogorily does not mention them but a few are shown on http://www.155la3.ru. The only ones I have are the 313А shown, dated January 1958, and the 316Г dated November 1958. I am seeking examples of a few others, with any suffixes, namely 320, 342, 343 and 347.

I also have this diode 1602Б dated June 1962. It is described on http://www.155la3.ru as a selected version of Д7Д.


GT308B transistor

As I state at the top, the later GT and 1T series are also germanium transistors, following State Standard 10862-64. The number groupings are:

These types use several outlines, including the 'MP'-style can, but not the original hot-welded 'top hat'.

I don't find these as interesting as the old П series, but they are germanium and some are quite old, so perhaps I should look into them more. The various editions of Marsden provide a timeline, although he is at least one year behind actual production. The types he lists are:

It's puzzling that some types disappear so quickly. All these series went on to have many more members. (Beware that ГТ types with numbers above 1000 are Bulgarian).

I don't intend to show any except this ГТ308Б (latin GT308B) fabricated in the cold-welded case in 1975. It is a germanium diffused-junction PNP general-purpose transistor.


GT110B transistor GT306A transistor

I have a couple of early transistors which don't seem to be listed in any of the data books:

If you know a source of data on these types, please


DK-V1 diode

Now let's turn to diodes. I am indebted to Andrei Chechnev (Андрей Чечнев) who has researched this area in detail and alerted me to his findings, published in the Russian magazine 'RADIO' for April and May 2020.

The earliest types were silicon point-contact diodes used as detectors for radar. Some Web pages state that they were copies of German devices such as the Telefunken ED702 that I show elsewhere. They have part numbers like КД2-И10, КД2С10А, КД2С3А, КД6В10А and КД6В3Б. My image shows the ДК-В1 (latin DK-V1) which is a silicon type that was manufactured from the 1940s into the 1980s and was previously called КД2В10. Like many radar diodes, it is supplied inside a lead sheath to protect against damage from static electricity.

wanted diodes

Possibly the oldest germanium diodes are the series of point-contact mixer diodes ДГ-В1 to ДГ-В8 from 1951. These were released publicly as ДГ-Ц1 to ДГ-Ц8 (latin DG-C1 to DG-C8) and the series was later extended to ДГ-Ц17.

There is also an obscure type СД1 that was briefly made but was technically defective.

I wish to obtain examples of any of these. If you know where I might get some, please

DG-C24 diode

Pogorily also describes an early group of germanium junction rectifiers ДГ-Ц21 to ДГ-Ц27 (latin DG-C21 to DG-C27) which were made from about 1956 onwards. The image shows a ДГ-Ц24 dated 1959.

VK7-1a diode

There are also some copper-oxide diodes to be found. My image shows the ВКВ7-1а (latin VKV7-1a) which is a low-current type made from 1957 and used in instrumentation. There are other older copper-oxide and selenium types but I shall not show them.


D2V diode

After 1956, diodes appear in what was to become the standard Д (latin 'D') series. Point-contact types use a typical glass encapsulation, but with the USSR metal ribbon leads as shown in this image of a germanium Д2В (latin D2V). The glass is unprinted and the part number and date are stamped into the metal ribbon leads, with a diode symbol showing the polarity. Д2 has suffixes А to Ж.

D1 diode

Type Д1 apparently does exist but I have never seen an example. While Д2 first appears in Russian databooks in 1957, Д1 appears only in 1962. Furthermore it is depicted as having normal wire ends rather than the ribbon leads of Д2. Andrei Chechnev has investigated it using documents only declassified in 2019: he finds a complex hidden history. You can read it (in Russian) on the computer-museum.ru site. Several semiconductor manufacturing facilities were involved and the same part number was even used for an entirely different power junction diode. It seems that diodes marked Д1 are hard to find. An assembly of two diodes Д1, matched by parameters, was used in TV discriminators and the like. This device was named ДК. If you know where I can get some Д1, please

D7J diode

According to Pogorily the ДГ-Ц2n rectifiers suffered from the case being poorly made and they were soon replaced by germanium medium-power type Д7 like this Д7Ж. (Latin D7ZH or D7ZHE and sometimes translated as D7J). There are seven suffixes:

There also exist a few other uncommon low-numbered Д types:


D303 diode

There are also moderately high-current rectifiers in stud packaging such as this 150V 3A germanium Д303 (latin D303) made by the Saransk plant, one of the series Д302 to Д305.


wanted diode

The 1963 Marsden book contains some germanium high-current rectifiers:

The suffix number denotes the maximum current in Amps, the ВГВ types are truly extraordinary. You can see the ВГ-10 and ВГ-50 on the www.155la3.ru web site. A few were once for sale on eBay but at a very high price. If you know where I can find any at a reasonable price, please


D101A diode

Work on silicon (non-microwave) diodes started in about 1955 in the USSR, so it's no surprise that Marsden 1963 contains several series:

The image shows Д101А and is typical of the silicon point-contact group in using darkened glass.


MD226B diode

This is an oddity. It's the only USSR diode that I have found that has the 'М' prefix. Д226 is a silicon rectifier with possible suffixes А, Б, В, Г, Д and Е according to Marsden. However my image shows an МД226Б. If you know about diodes with the М prefix, please


D808 Zener diode

According to www.155la3.ru the first USSR Zener diodes were

These were piloted at NII-35 (now 'Pulsar') in 1958 but production was switched to 453 URTP, later Novosibirsk plant. My image shows a Д808 dated February 1963.

However, Marsden 1963 also lists Zener diodes:

Something seems to be wrong here, as Д6 and Д8 are found nowhere else, and Д7 also appears in the rectifying diode section of the book, albeit with suffixes. However the trio is retained in subsequent editions, which add more Д81n types, some with multiple suffixes. Original USSR databooks do not contain Д6, Д7 or Д8.


USSR photodiode

The USSR made a series of photodiodes ФД1, ФД2 etc. (Latin FD1, FD2 etc) of which the earliest members are germanium. I only have the odd flat plastic ФД2 and the more conventional tubular ФД3-A shown. If you know where I can find others, especially ФД1 , please

wanted diode

The USSR also made a series of germanium phototransistors. The earliest types come in a black 'top hat' outline like many of the П series, but with a transparent window in the top. They start with ФТ-1 (Latin FT-1), ФТ-2, ФТ-3 etc., but may have a suffix ФТГ-n. If you know where I can find examples, please There are also silicon phototransistors in a more modern outline with a suffix К such as ФТ-1К. I am NOT seeking these.


From the mid-1960s the USSR manufactured silicon controlled rectifiers, or thyristors. The 1963 Marsden book contains none, but the 1965 edition has several series:

switch control diode

Two devices are nowadays described as thyristors but are listed in Marsden as 'diodes - switch control' and appear in the USSR 'Д' series:

My image shows the rather chunky Д238Г with three heavy wire leads. It is a 20W device. I'm unsure of the manufacturer and I speculate that the 'К' stands for 'кремний' which translates as 'silicon' although that could well be wrong.

Then Marsden lists the following thyristors, so 'switch control' is not just an early name for that device, but must signify some difference.

The first number is the max forward current in amps with forced air cooling, except for the ВКУВ types, which use water cooling. The second number is the max PIV in kilovolts.

These seem to be relatively rare. On eBay there are none, just later thyristors in the T and KU/2U series.


The USSR also made tunnel diodes. Again Marsden 1963 lists none but Marsden 1965 lists two series:

In Marsden 1967 these have been joined with:

I would be interested to obtain any of the germanium ones. If you know where I can find any, please


Of course the USSR went on to make integrated circuits starting in about 1964. The earliest ones are of some interest and I have created a separate page for them.