After its foundation in 1928, one of the central projects at the Research Laboratory (FI) of the German electrical company AEG was the development of Braun tubes and oscillographs. The example of the oscillograph can be used to show how a laboratory device was transformed into a technical system, how this system was conceived by different groups of actors (physicists, electrical engineers, management), and how it changed its form and function under changing requirements.

I am particularly interested in the role played by physicists and their expertise in this development. At the FI, the physicist Ernst Brüche and his colleagues tried to establish geometrical electron optics as a new branch of physics. They perceived the manipulation of 'free electrons' in Braun tubes as an interesting field to test their ideas, theories and methodologies. In my talk, I will discuss how these physicists negotiated with members of other groups what kind of physics, what tools, theories and experiences they could offer as suitable contributions to the development of oscillographs and other electronic devices. Did they manage to follow and establish their own agenda? How did they adapt their expertise, their ideas and methodologies to the needs and conventions of an industrial environment (e.g. communication with engineers and technicians, adaption to the conditions of mass production and the demands of patent law)?