Tungsram logo

The long-established Hungarian electrical manufacturer Tungsram famous for the production of electric lighting, produced germanium diodes and transistors. They seem to have started by copying some USSR types, moved on to the Mullard/Philips OC series, and then the standard pro Electron series AC, AD, AF and possibly others. They also produced devices in some Eastern European series, and diodes in the OA and AA series. The history of Tungsram is documented in two books (in Hungarian): 'A Tungsram Rt. története, 1896-1996' and 'A TUNGSRAM márka története'. Tungsram is a Hungarian brand, and not a single factory. The main factory was Egyesült Izzólámpa és Villamossági Rt..

A confusion is caused because Tungsram originally had three valve/tube factories in London, one being the 'British Tungsram Radio Works', in West Road, Tottenham. The brief entry in Graces Guide states that 'British Tungsram' was taken over by Philips/Mullard in 1952. It apparently continued to sell valves and eventually semiconductors under the brand 'TUNGSRAM', which implies that semiconductors marked 'TUNGSRAM' may not be Hungarian. Such devices cannot, however, bear the Tungsram logo. I have created a separate web page for British Tungsram.

Thanks to Miklós, a correspondent and fellow enthusiast, I have scans of a number of early Tungsram data catalogues, the earliest dated 1960. It includes some semiconductor diodes and transistors, details below.

Miklós has also sent me information about the history of another Hungarian semiconductor: Konverta Egyenirányító Gyár (Konverta Rectifier Company). As an independent state-owned company in the 1950s, Konverta was given the task of taking over the production of germanium and silicon alloy rectifiers as it was already in charge of selenium rectifier production. However, development of the germanium type was placed in the Bródi Laboratory of Izzó (Short name of Egyesült Izzó Ltd, the official name of Tungsram) led by Dr. Iván Szép. The TKI (An other development company) was commissioned to develop silicon rectifiers, with deadlines of 1-2 years later than for germanium devices. Production of prototyped germanium diodes began in 1960-61. Konverta was merged into Tungsram in January 1963.

If you can provide more detail about Tungsram or Konverta germanium devices, please

P6 transistor

One source of information about early Tungsram devices is an article by Simoncsics László which was published in the Hungarian magazine 'Radiotechnika' in 2016. In one paragraph he says that 'Radiotechnika' started reporting on semiconductors in 1957. He goes on to say that Tungsram's first transistors were copies of the USSR type П6, made from about 1955. My image shows one of these, its printing rather worn. (Please note, especially radiomuseum: the Hungarian language does not use the Cyrillic alphabet!) I don't know why there is just a letter T rather than the Tungsram logo, I suspect that is an indication of its age, and the other P types below are the same.

I have no original data for this type P6, nor indeed any real data at all. if you know where I can get some, please

P13B transistor black P13B transistor

My scanned Tungsram data catalogue for 1960 lists five transistors: P13, P13A, P13B, P14 and P15. These use the same outline as the P6 but were Tungsram development, not copies of USSR types. P6 is not listed.

There are images of some of these devices on the Web. The Orionette 1004 radio uses two P14 as AF amplifiers and a pair of P6 as output transistors. (Interestingly, that page lists the output transistors as 2P6, suggesting that a matched pair was sold). The P13 is shown on the radiomuseum site.

The images show two variants of P13B in an encapsulation that is very similar to early USSR transistors. I suspect strongly that the number under the part code on one is a date code in the format month-year, so that P13B coded 88 was made in August 1958. I don't know whether the black-painted one, kindly donated to me by Erno in Hungary, is earlier or later.

wanted transistor

I would like to obtain more examples of these P types, the P6x ones in particular. If you know where I might get some, please

P13AT transistor

My scan of the Tungsram catalogue for 1963 contains some P-series types in what was to become Tungsram's standard outline for low-power transistors, a metal cylinder similar to SO-2 or TO-1.

The catalogue contains:

  • P13T, P13AT, P13BT, P14T, P15T and 2-P6T (matched pair).

The original P types are not listed, so these must have superseded them. My image shows the P13AT

Tungsram OC1016 transistor
Tungsram OC1072 transistor
Tungsram OC1044 transistor
Tungsram OC1045 transistor

Tungsram made germanium transistors in the Philips/Mullard OC series, but for most of them they added 1000 to the original part number. A Hungarian data book (7.6MB pdf) from 1960 by Házman and Hrabál lists the following:

  • OC1016 equivalent to the OC16 high-power output transistor. The 1963 catalogue shows the TO-3 outline as above, but it may have been made briefly in the OC16-style stud outline. I would be interested to get such an example.
  • OC1072 equivalent to the OC72 medium-power output transistor (second from left above, in a clip-on heatsink fin).
  • OC1044 equivalent to the OC44 RF oscillator/mixer (second from right above).
  • OC1045 equivalent to the OC45 IF amplifier (rightmost above).

I believe that the black-painted ones are the earliest and I am seeking a black example of OC1044.

Tungsram tubes and transistors are often printed with a proprietary two-character date code. The values are shown here, although the case (upper/lower) of the letter seems to be sometimes wrong. My OC1016 above is coded r9 which I believe to be September 1963 (code R9, there is no r9 in the table).

Tungsram made other transistors equivalent to OC types, starting later than 1960. The 1963 Tungsram catalog lists:

  • OC1070, OC1071, OC1072.

The 1966 Romanian databook 'Catalog de Dispozitive Semiconductoare' by Veronica Vătăşescu and Şerban Epure, which you can download from the Web, lists

  • OC1070, OC1071, OC1072, OC1074, OC1075, OC1076, OC1077, and OC1079.
Tungsram OC1074 transistor Tungsram OC1071 transistor Tungsram OC1070 transistor

Here are:

  • An unpainted OC1070, two black-painted OC1071s and an unpainted OC1074. They are equivalent to the Philips/Mullard OC70, OC71 and OC74 PNP low power AF amplifier types.
Tungsram OC1077 transistor Tungsram OC1075 transistor
  • OC1075 equivalent to a Philips/Mullard OC75 PNP low power AF amplifier. It is printed TUNGSRAM rather than bearing the logo and it has a flatter top than my other OC107x types.
  • In the same photo an OC1076 equivalent to a Philips/Mullard OC76 PNP medium-power switch.
  • OC1077 equivalent to a Philips/Mullard OC77 PNP medium-power switch.
Black Tungsram OC1079 transistor Tungsram OC1079 transistor possible Tungsram OC1079 transistor
  • The left image shows an OC1079 (equivalent to an OC79 AF output driver) in an outline similar to the Philips/Mullard SO-2 original. It is printed TUNGSRAM rather than bearing the logo, which raises the possibility that it was made by British Tungsram, although the construction does not look exactly like a Mullard type. However, this is the only Tungsram transistor that I have ever seen in this outline. The middle image shows an OC1079 in the usual version of the TO-1 outline with the Tungsram logo (thanks to Viktor for donating this). I also have a black-painted version shown on the right, in an elongated TO-1 shape, again with the logo that proves it is Hungarian Tungsram.

The 1966 Romanian databook mentions a Tungsram type OC1080 in a brief note. However no such type exists in early Tungsram databooks.

I am seeking black versions of OC1044 and OC1070. If you can help with that, please

Tungsram OC44F transistor

This image shows a pair of Tungsram transistors clearly marked OC44F. I'm grateful to Erno in Hungary for donating these, however, neither he nor I can find this type in any data book! If you can provide data, please

Tungsram AC125 transistor

Considering now the pro-Electron numbering, I have a Tungsram catalogue for 1966 that lists the following germanium types:

  • AC107 - an image on Wikimedia Commons shows this in Tungsram's standard metal outline rather than the glass envelope that Mullard/Philips uses
  • AC125, AC125F, AC125(z), AC125F(z), AC125K(z), AC125U(z) - AC125 on the left is a PNP germanium alloy transistor for AF pre-amplifier applications, equivalent to the Mullard OC70 or OC71.
  • AC126, AC128, 2-AC128, AC128(z)
Tungsram AD1204 transistor Tungsram AD1202 transistor
  • AD1202, AD1203 and AD1204 the last of which was added in 1969. I'm seeking AD1203 to complete the set!

Thanks to Erno I know that the code HM that appears on these transistors means Honvédelmi Miniszterium = Ministry of Defence.

  • AF106, AF134, AF135, AF136, AF137
20:49 18/02/2024
Tungsram ASZ101n transistors
  • ASZ15, ASZ16, ASZ17, ASZ18
  • ASZ1015, ASZ1016, ASZ1017, ASZ1018

The ASZ versions with 1000 added have lower maximum ratings than the 'original' types. Thanks again to Erno for these.

Tungsram AC188K transistor

The Tungsram 'Handbuch der Transistoren' 1969 has added:

  • AC127, AC128U
  • AC176, AC176K, AC187, AC187K, AC188, 2-AC188, AC188K, 2-AC188K
  • AD149, 2-AD149 matched pair, AD150, 2-AD150 matched pair
Tungsram AD161 transistor
  • AD161, AD162, 2-AD162 matched pair, AD162U
  • 2-AD1202 matched pair, 2-AD1203 matched pair
  • AF109R, AF139, AF200, AF201, AF202, AF239
  • AU106, AU107, AU108
  • AFY12
Tungsram ASY78T transistor

On the left is what appears to be a Tungsram ASY78T, although the logo does not seem quite right. This type is not found (nor is any other ASY type) in any Tungsram documentation of which I am aware. If you know where I can find original data for this device, please

Considering now early diodes, I turn again to the Hungarian data book from 1960. It lists two series of germanium point-contact diodes by Tungsram:

GD2 diode
  • GD1, GD2A, GD2B, GD2C, GD5A, GD5B, GD5C, GD10A, GD10B, GD10C

These do not appear in the Tungsram catalogue, and the naming makes me wonder if they are copies of USSR devices. However, I have been fortunate enough to obtain the diode shown on the right, marked GD2.

If you know where I can find information about, or examples of, these GD diodes, please

  • OA1150, OA1154Q, OA1160, OA1161, OA1172

These are all glass axial point-contact diodes and I believe that they are equivalent to Telefunken types without the '1000' added, for example OA1150 is equivalent to Telefunken OA150. These are shown in the images below, which show early examples with a coloured decal on the body; later examples just have black printing on the glass.

Tungsram OA1150 diode
Tungsram OA1154Q diode
Tungsram OA1160 diode
Tungsram OA1161 diode
Tungsram OA1172 diode
OA1161 diode pairs

I also have some OA1154 without the Q suffix but with a green decal: I would be interested in original data for this type. The type OA1161 was sold in matched pairs denoted 2-OA1161, as shown by the rightmost image above. Possibly other OA types were too, but I have no data for such pairs. If you do, please

OA1182A diode OA1180 diode

Tungsram documents list three more OA types: the gold-bonded diodes OA1180, OA1182 and OA1182D. My images show the first of these with a rather fetching purple decal, and a type OA1182A that I cannot find listed.

I am seeking examples of OA1182 and OA1182D with decals on the body (rather than later examples with printing on the glass), plus original data for OA1182A. If you know where I can get any, please

Tungsram also made glass-bodied point-contact types in the GA and GAZ series, but the 1960 Hungarian data book does not list them. These are Eastern European series.

AA113 diode

Tungsram's 'Electron Tubes and Semiconductors' from 1976 lists the pro-Electron types:

  • AA112, AA113 (shown, thanks again to Viktor), AA116-AA119, AA132, AA135-AA137, AA139
  • 2-AA112, 2-AA113, 2-AA116, 2-AA118, 2-AA119 diode pairs
  • AAZ10

I have a scan of a Tungsram diode databook from 1966 that includes:

  • AY101T to AY107T germanium 3 Amp axial-outline diodes, these types (without the suffix T) were made by SGS in Italy

The 1960 Hungarian data book has sections on germanium junction diodes and silicon diodes, but there are no Tungsram types listed.

GEN-55 diode

Diodes from Konverta are harder to find and I'm grateful to Erno for sending me several types. I know that they made:

  • GDK-1 to GDK-7 germanium 300 mA axial-outline diodes
  • GEN-51 to GEN-55 germanium 5 Amp stud diodes. The image shows the chunky GEN-55, branded KONVERTA and date coded 6512.
SIEK-4 diode
  • SIEK-1 to SIEK-7 silicon 5 Amp wire-ended stud diodes. The image shows SIEK-4, branded TUNGSRAM and date coded 6803.

As with my SIEK-4, later production may be branded Tungsram, or even possibly HWF, because in 1962 Konverta transferred the technology for the production of germanium rectifiers to the Frankfurt(Oder) semiconductor factory in the GDR free of charge.

There are higher-numbered diodes in the Tungsram SIEK series, and indeed reverse polarity versions with a suffix 'R'.

I would be interested to obtain Konverta-branded examples of any GDK diode, to complete my line-up.

Of course Tungsram went on to make other silicon diodes and transistors, and indeed integrated circuits, but I shall not show those here.