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 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 RL diodes

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. They appear to have made point-contact diodes in the V, R and RL series.

The top image shows a couple of RL-series diodes, RL120 and RL122. I believe these date from the late 1950s, but I don't think they are some of their earliest types.

Siemens RL32g diode

The lower image 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 a metal RL32.

I am interested in obtaining other diodes in the V, R and RL series, especially low-numbered ones such as R1, V3 and RL6.

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 buying 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 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 used the VASCA SO-2 glass bulb typical of Philips devices.

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


Siemens TF49 transistor

This image shows the TF49 and TF65 transistors. These and a number of other TF types used this bulbous package that approximates to JEDEC TO-1. Again however, I have no definitive data on them.

Some of these types also exist with an 'S' suffix, and use a black-glass case similar to VASCO SO-2 (eg Mullard/Valvo OC71 shape). I am interested in obtaining examples of these, so if you know where I can get any, please


Siemens TF71K transistor

Transistor shapes become odder when we reach the TF70 range. 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".

I'm aware of the existence of a TF70 type, I am interested in buying or trading for it, 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.


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.


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.


Siemens TF80 transistor

The last TF type I show is the TF80 high-power transistor rated at 6 watts. 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 wanted

the TF85 is another weirdo: a blue hexagonal bolt with lugs similar to the TF75 but larger.

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


Siemens TF90 transistor

There is also a TF90 with the same shape as the TF80. For completeness I am seeking examples of this.


Siemens AD105K transistor

Siemens went on to make many types of germanium transistor in the standard pro-Electron AC, AD, AF and ASY series, using fairly standard packaging. I shall not show these except for the AD105K on the right, which 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 use the same shape.


Siemens SD50 diode

Turning to diodes, my 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.

If you have original data for this device, please


Siemens 1E diode

Here are some diodes with tantalisingly low part numbers: 1E, 2E and 6E. I believe that these are gold-bonded detector diodes, and are not Siemens earliest types.

If you have original data for these devices, please


Siemens made many other semiconductors: germanium and 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!








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