Siemens transistor logo

The German electrical giant Siemens and Halske was founded by Werner von Siemens and Johann Georg Halske on 12 October 1847 to develop products for the early telegraph. It has since diversified into almost all aspects of the electrical industry and is now the largest engineering company in Europe.

Siemens has been manufacturing semiconductors since the 1950s. Most of them bear the logo shown on the right, formed by the combination of the letters S and H.

I have a few data books for Siemens semiconductors. The oldest is 'Crystal Diodes' a booklet that I guess dates from about 1953. It contains only RL series diodes. Then I have a 'Siemens Transistoren' booklet that I believe to date from 1959. It contains the following transistors, all germanium PNP types:

There is an earlier book: 'Transistor Praxis' by Heinz Richter, dated 1956, that lists the type TF65.

I am seeking to buy or trade for certain germanium transistors and diodes made by Siemens. Details are given below. I also want to buy original data sheets for many of their devices. If you know about these transistors, or have have some for sale or trade, please

Ich suche, die Germaniumtransistoren zu kaufen, die von Siemens im Jahren 1950's und 1960's hergestellt werden. Ich suche nach den Transistoren, die nachstehend aufgeführt werden. Ich möchte auch ursprüngliche Leistungsblätter für sie kaufen.

Wenn Sie in diesen Transistoren auskennen oder haben, einiges für Verkauf oder Handel zu haben, in Verbindung.


Siemens V3 diode

I expect that the first semiconductors that Siemens made were diodes, since most semiconductor manufacturers started that way. However I am unsure about their earliest devices. Some of the earliest appear to have been point-contact diodes in the V and R series, although I have no data references except the radiomuseum site and it does not give a reference or date. The only V type I have is this V3, although I have some GD1P and GD5E in the same crude outline. Those can be found in the D.A.T.A. book 'Semiconductor Diode & Rectifier Characteristics Tabulation 1961 vol VII': they also are germanium point-contact types.

Siemens 1E diode

Here are some diodes with tantalisingly low part numbers: 1E, 2E and 6E. Assuming they have the prefix GD, they can be found in the D.A.T.A. book 'Semiconductor Diode & Rectifier Characteristics Tabulation 1961 vol VII': they are germanium point-contact types and appear to be an improved packaging of the GD series mentioned above.

Siemens RL32g diode

This shows a rather plain RL32g glass-bodied diode. I think the suffix g denotes the glass body, and this may be a later version of the metal RL32 that appears in the D.A.T.A. book 'Semiconductor Diode & Rectifier Characteristics Tabulation 1961 vol VII': it is a germanium point-contact type. The RL series went on to higher numbers 1nn and 2nn. Rather puzzlingly, the 1954 book 'Kristalloden Technik' by Rost mentions only RLnnn types with numbers greater than 100.

Siemens SD50 diode

This image shows an SD50 junction diode in a very crudely shaped and painted package. It looks like an attempt at the VASCA SO-2 glass bulb. It is found in the D.A.T.A. book 'Semiconductor Diode & Rectifier Characteristics Tabulation 1961 vol VII': it is a silicon diffused-junction type and the radiomuseum entry suggests that it is not particularly early.

If you know about Siemens earliest semiconductors, or have have some for sale or trade, please


Siemens point-contact transistor

The first transistors that Siemens made were the point-contact types TS13 and TS33, which are packaged in the typical cartridge case shown.

I am very interested in finding examples or original data sheets for these devices so if you know about these transistors, or have have some for sale or trade, please

Siemens PCTs wanted

Siemens TF44 transistor

Siemens then progressed to making germanium junction transistors in a proprietary TF series. (You might expect that to be a Telefunken series, but it is not). This contained a number of early types in idiosyncratic packaging, a delight to a collector such as myself. However I do not possess a definitive list of all the types in the series. The lowest-numbered example that I have is the TF44, which uses the VASCA SO-2 glass bulb typical of Philips devices. According to the wonderful radiomuseum site, this is a germanium PNP junction type for use as a low power oscillator/mixer in AM radio circuits.

If you have original data for the TF44, or the TF series transistors in general, please


Siemens TF49 transistor

This image shows the TF49 and TF65 transistors. These and TF66 use this bulbous package that approximates to JEDEC TO-1. They are included in 'Siemens Transistoren' and are germanium PNP types, TF49 being for RF use, TF65 and TF66 (which has several possible suffixes) for AF.

Radiomuseum also shows a TF65S in a black-glass case similar to VASCO SO-2 (eg Mullard/Valvo OC71 shape). I am interested in obtaining examples of TF65S, so if you know where I can get any, please


Siemens TF90 transistor wanted

Transistor shapes become odder when we reach the TF70 range. Radiomuseum shows a TF70 in an oval outline which is an NPN germanium transistor for AF pre-amplifier applications.

Siemens TF71K transistor

My image shows a TF71K. There exists also a TF71 without the aluminium block: according to the radiomuseum page it has an oval can that seems to match the shape of the filled hole in my K type. The use of suffix K to denote a heatsink is continued in other series by Siemens and other German manufacturers: I believe it is an abbreviated form of 'Kühlkörper', the German for 'heatsink'. According to radiomuseum this is an NPN germanium junction transistor intended as AF low power amplifier / driver.

I am interested in buying or trading for TF70 as well as the TF71 without heatsink. I'm also looking for data on these.


Siemens TF72 transistor

Here is a TF72, also in the oval can. According to the 1969 'Book of Discontinued Transistors' by D.A.T.A. it is a germanium PNP low power audio frequency amplifier.

The only data I have for TF70, TF71 and TF72 comes from radiomuseum or D.A.T.A. If you know where I can get any original data, please


Siemens TF75 transistor

This TF75 is possibly the strangest shape of any transistor made in the world, ever. It looks like a hexagonal nut on a threaded screw, but with hooks out of three of the faces. Radiomuseum dates it to about 1955, but I have found it in 'Tous les Transistors' for 1959 and the Hungarian data book (7.6MB pdf) from 1960 by Házman and Hrabál. It is, as you might expect, a germanium PNP medium power audio frequency amplifier.


Siemens TF78 transistor

We return to normality with the TF77 and TF78 (shown), which use simple cylindrical cans denoted as VASCA SO-22 or JEDEC TO-8. These and subsequent Siemens TF numbers often bear a suffix denoting a voltage rating, for example my image shows a TF78/60. Examples without a suffix also exist; I do not know what the default rating is. TF78 is another germanium PNP high-power audio frequency amplifier.


Siemens TF80 transistor

TF80 is a germanium PNP high-power transistor rated at 3 Amps collector current, 6 Watts dissipation. It uses a large cylindrical can apparently denoted R58, with the three leads grouped unconventionally at the centre. It exists with a variety of suffixes.


Siemens TF85

The TF85 is another weirdo: a blue hexagonal bolt with lugs similar to the TF75 but larger. The only data I have found for it is the Házman and Hrabál book which states it is a germanium PNP high-power audio frequency amplifier.

I'm very keen to buy or trade for these so if you know where I can get any, please


Siemens TF90 transistor

This TF90 is marked 'ENTWICKLUNGSMUSTER' which translates as 'development pattern' and implies that it is a prototype. It too is a germanium PNP high-power transistor, rated at 15 Amps collector current, 23 Watts dissipation, in a case similar to TF80. The 'Siemens Transistoren' booklet and radiomuseum.org both only list variants with suffixes /30 and /60.


Siemens TF260 transistor wanted

I believe that Siemens also made silicon NPN medium-current types TF251, TF252 and TF260. They are not in radiomuseum.org and I don't know what they look like but I would be interested to obtain one.


Siemens AD105K transistor

Siemens went on to make many types of germanium transistor in the standard pro-Electron series, using fairly standard packaging. I shall not show these except for the AD105K on the right, which is included in 'Siemens Transistoren 1960'. It has a rather unusual case similar to the TF80 above but slightly larger. I'm unsure why this device has the K suffix, as it does not have an attached heatsink. The AD103 and AD104 have the same shape.

The book 'Siemens Halbleiter Datenbuch 1967/8' lists the following germanium devices (but not the AD10n trio):

'standard types'

'industrial types'


Siemens made many other semiconductors: silicon diodes and transistors in various standard series, and then integrated circuits. Indeed they still manufacture those today. However all of these are too modern for this page of my collection!