Something about the German classification
German Transistors had two
letters and two or three numbers for type identification.
The first letter was the
“O“ , showing that this device needed no heating compared to electronic
The second letter was the
letter “C“ , showing this was a triode . This C was used for tubes as
i.e. EC92 , which was
If the second letter was a
“D“, this transistor was a “power“-type , which at that time could be
some hundred milliwatts or even some watts.
VALVO used two-digit
numbers for classification, as well as TEKADE and SIEMENS & HALSKE.
TEKADE hadt a
classification of its own. Their transistors started with GFT (for
germanium junction transistor ), whereas TELEFUNKEN used three-digit
numbers, as did INTERMETALL.
© Rudolf Herzog , Germany