Tungsram logo

I have little information about the early manufacture of semiconductors in Hungary. The long-established Hungarian electrical manufacturer Tungsram, (still in existence today) famous for the production of electric lighting, produced germanium 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..

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 manufactured semiconductors, which implies that semiconductors marked 'TUNGSRAM' may not be Hungarian, and I show one example below. Such devices cannot, however, bear the Tungsram logo. British Tungsram changed its name to 'Tottenham Radio Valve Co. Ltd.' and its branding to 'TORVAC' in the early 1970s.

The only original Tungsram semiconductor data books that I possess are downloads of 'Electron Tubes and Semiconductors' from 1976 and 1979. These are rather late and include many more silicon devices than germanium ones.

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


P13B 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 types П6, П13, П14 and П15 made from about 1955.

This is further substantiated by a Hungarian data book (7.6MB pdf) from 1960 by Házman and Hrabál. This is not limited to Hungarian types, but on pages 73 and 74 it lists Tungsram germanium PNP types P6A, P6B, P6V, P6G, P6D, P13, P13A, P13B, P14 and P15. The suffixes follow the convention and the order used by the USSR, although the Tungsram part numbers are not in the Cyrillic alphabet.

Finally, we can see 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, a schematic that I can no longer find showed the output transistors as 2P6, suggesting that a matched pair was sold). The P13 is shown on the radiomuseum site.

This image shows a P13B. These P types use an encapsulation that is very similar to the USSR 'modernised-П' cold-welded can. I don't know why there is just a letter T rather than the Tungsram logo. I suspect strongly that the number under the part code is a date code in the format month-year, so my P13B coded 88 was made in August 1958.

wanted transistor

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

P13AT transistor

A puzzle that I have found are some Tungsram P13AT transistors as shown. I assume that these are indeed P13A, and the extra suffix T denotes that they are in the TO-1 encapsulation rather than the USSR MП type.

If you have any data for these, please


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. The 1960 book by Házman and Hrabál lists the following:

  • OC1016 equivalent to the OC16 high-power output transistor. My example is in the TO-3 outline (leftmost above), but old books show it 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 made other transistors equivalent to OC types, presumably starting later than 1960. The 1966 Romanian book '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, OC1079 and OC1080.
Tungsram OC1074 transistor Tungsram OC1071 transistor

Here are:

  • A black-painted OC1071 and an unpainted OC1074 equivalent to the Philips/Mullard 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.
Tungsram OC1079 transistor
  • 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. I have seen an image of black-painted OC1079 in an elongated version of the TO-1 outline.

I am seeking a black OC1070, an example of a Tungsram OC1080, and other shapes of OC1079. If you can help with that, or have original data for any of these OC10xx types, please


Tungsram AC125 transistor

Considering now the pro-Electron numbering, here is a Tungsram AC125 in the TO-1-like package. This common type is a PNP germanium alloy transistor for AF pre-amplifier applications, equivalent to the Mullard OC70 or OC71.

Tungsram AC128 transistor

And here is an AC128 in the standard TO-1 package, sold in a rather nice metallic tube that bears the words 'TUNGSRAM SEMICONDUCTORS' plus the London address, and was therefore made by 'British Tungsram'. It is a germanium PNP AF output type and is probably really a Mullard device. I have seen images of Tungsram AC128 in the same outline as the AC125 above, and bearing the T logo, which is true Hungarian manufacture.

I would be interested to find transistors branded 'TORVAC', which may come in a similar tube.

Tungsram AC188K transistor

This is a Tungsram AC188K in the standard Telefunken outline with aluminium block heatsink, the suffix K denoting 'Kühlkörper' or 'Kühlklotz'.

Tungsram AD161 transistor

And here is a Tungsram AD161 AF power type.

'Electron Tubes and Semiconductors' from 1976 lists the following Tungsram germanium power transistors:

  • AD161, AD162, ASZ15 - ASZ18, ASZ1015 - ASZ1018, OC26

The ASZ versions with 1000 added have lower maximum ratings than the 'original' types.

Ebay usually has a few more genuine Tungsram power types such as AD1202 and AD1203, plus some wrongly-attributed ones.


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:

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

I do not know what these look like. The naming makes me wonder if they are copies of USSR devices.

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

OA1180 diode

Tungsram made three more OA types: the gold-bonded diodes OA1180, OA1182 and OA1182D. My image shows the first of these with a rather fetching purple decal. I am seeking examples of OA1182 and OA1182D with decals on the body (rather than later examples with printing on the glass).

If you know where I can get any, please

Tungsram also made glass-bodied point-contact types in the AA, GA and GAZ series, but the 1960 Hungarian data book does not list them. The last two are Eastern European series. Tungsram's 'Electron Tubes and Semiconductors' from 1976 lists

  • AA112, AA113, AA116-AA119, AA132, AA135-AA137, AA139
  • 2-AA112, 2-AA113, 2-AA116, 2-AA118, 2-AA119 diode pairs
  • AAZ10

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


wanted transistor I believe that Tungsram made a series GEN51 - GEN55 of germanium 5 Amp rectifier diodes. A Hungarian correspondent has informed me that these were products of Konverta Egyenirányító Gyár (Konverta Rectifier Company - another Hungarian company) which was merged into Tungsram in January 1963. I would be interested to obtain examples.

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