Transistor Museum Lecture Hall

 “The Early History of Transistors in Germany”


Rudi Herzog (Continued)




At the Industrial Fair in April new junction transistors appeared:


TELEFUNKEN showed the OC603 (low-noise) and OC604 for small power uses.


TEKADE  showed up with the GFT20 (junction type ) and some GST-1 and GST-2 point-contact devices.


VALVO presents the OC72 (small power amplifier). Power dissipation for OC70, OC71 were exceeded to 25 mwatts.


S.A.F. has junction types OC110, OC120, OC 130.


SIEMENS produces TF65 (universal application like CK722 ).

General purpose transistors sell for DM 13,75 ($ 3.25 )


In fall of 1955 many medium-power-transistors appeared :


TELEFUNKEN came with the OD604.


INTERMETALL presented X-125, X-122, X-120 (15 watts ).


SIEMENS & HALSKE had the TF75 ( 250 mW ) and TF85 ( 4 watts )

Still no RF – transistors were available!








Rudi Herzog (Continued) 


During the 1955 Industrial Fair in Hannover, TELEFUNKEN showed a transistor-radio sample only “behind a curtain“ to interested radio-manufacturers - but not publicly. GRUNDIG, which was a main customer for TELEFUNKEN-tubes at that time, urged TELEFUNKEN to postpone the public presentation and production of a transistorized radio or would otherwise quit on buying any more tubes. And the tube-business with GRUNDIG was a very important one. This TELEFUNKEN transistor radio (called TR-1) was mainly based on the TR-1 Regency .  It seems that some of the components of the Regency TR-1 were used in the TELEFUNKEN radio as well.  Could these be from a cannibalized Regency?  As still no German RF-transistors were available selected samples of the OC602 AF-type were used for the R.F. stages. Radio operated from 22,5 volts-battery.  TELEFUNKEN decided to manufacture only 400 sets for field application and gathering of experience on this new technique.  Most of the sets were given to TELEFUNKEN salesmen all over the world and the US. They never appeared in retail and so they are highly appreciated sets with collectors today.







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