Like Siemens, the German company Telefunken was founded in 1903 to develop products for the early telegraph. Also like Siemens it has diversified and grown into a major international player in the fields of consumer electronics and industrial goods.

Telefunken transistor

Telefunken has been manufacturing semiconductors since the 1950s. Its devices do not normally bear a logo, simply the letters TFK.

The history of Telefunken semiconductor manufacture has been comprehensively documented by Mark Burgess. There is little point in me repeating information that he provides, so this page is just a display of some interesting TFK devices.

I am seeking to buy or trade for certain germanium transistors and diodes made by Telefunken. 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 Telefunken 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.


Telefunken ED702e diode

My overall page on Germany shows some Wehrmacht radar diodes ED704 that were manufactured by Telefunken during the late 1930s. This image shows similar devices, type ED702e.

I am very interested in obtaining definitive data on these diodes. If you know about them, or others of Telefunken's earliest semiconductors, or have have some for sale or trade, please


Telefunken OA161 diode

According to Mark, the first post-war semiconductor products from Telefunken were germanium point-contact diodes types OA150, OA159, OA160, OA161, OA172 and OA173. My image shows an OA161 which is a high-reverse-voltage diode with a maximum peak inverse voltage of 120V.


Telefunken point-contact transistors

Telefunken experimented with germanium point-contact transistors, and may have exhibited some of them at trade shows, but these were not commercialised. The only one to have a known part number is the GC1.

I am very interested to obtain such transistors. If you know about them, or others of Telefunken's earliest semiconductors, or have have some for sale or trade, please


Telefunken OC601

Telefunken then moved on to junction transistors, starting with the types OC601 and OC602 in 1954. The first versions of these used a flat case as shown in my image, unique in bearing the full Telefunken logo. By 1955 Telefunken had adopted a cylindrical glass tube similar to the VASCO SO-2 encapsulation familiar from the Mullard OC71 etc., shown below for higher-numbered OC6xx types.

I am very interested to buy or trade for the flat-case OC601 and OC602. If you know where I can obtain them, or have have some for sale or trade, please


Telefunken OC603

Next came the AF amplifier types OC603 and OC604 in 1955 using the black glass capsule. I do have some OC603 but they are sealed inside original cartons as in the image.

I am looking for OC603 and OC604. If you know where I can obtain them, or have have some for sale or trade, please


Telefunken OD604

Again according to Mark, in late 1955 Telefunken showed their first power transistor, the OD604. This is an oddity. Like many early attempts to increase power dissipation it clamps a metal heatsink around a transistor in a smaller encapsulation. This was the first of several idiosyncratic power transistor designs from Telefunken.


Telefunken OD603

Telefunken subsequently issued several power transistors in a squat cylindrical can with three leads issuing from a hole in the baseplate. The first was the OD603. Oddly, this seems to have been issued in 1958, several years after OD604.

The image shows unpainted and grey-painted examples. There exist also black-painted versions. Furthermore, the device may have several maximum-voltage values and this is sometimes indicated by either a suffix or a number printed on the can.

Telefunken ALZ10

The ALZ10 used the same can.

Telefunken AUZ11

As did the AUZ11.


Telefunken OD605

The last in the idiosyncratic trio of OD series power transistors is the OD605, a black-painted cylindrical type larger than the OD604 and capable of 15 Watts dissipation.

I am interested to buy or trade for exmples of OD605. If you know where I can obtain them, or have have some for sale or trade, please


Telefunken OC612

The OC series continued with several OC61x types as shown, using the SO-2 glass capsule.


Telefunken OC602SPEZ

An oddity in the Telefunken range is that several of the glass tube types exist in physically longer versions enclosed in a small metal heatsink and distinguished by the suffix 'SPEZ' (for 'spezial' presumably). My image shows the OC602SPEZ, which is unique in my collection in having two forms, one just a metal tube around the glass, the other with a metal fin that can be bolted on to further heatsink material.


Telefunken AC150

Telefunken went on to manufacture many devices in the standard pro-Electron AC, AD and AF series, many in the tall TO-1A can such as this AC150.


Telefunken AD138

Here is an interesting example in the AD series: the AD138 AF power amplifier. It uses the TO-3 can, but is painted in a rather military-looking dull green-blue, and is still supplied in a valve box, even with an image of a valve on it. (the end flaps are stamped AC138).


I don't intend to show them, but of course Telefunken went on to issue many silicon transistors and diodes.








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