Theodor Wasserrab was fascinated by power converter technology, and spent 10 years researching solutions to existing problems at Siemens Schuckert-Werke in Berlin. From 1949 Wasserrab held a lectureship in power converter technology at the Technical University of Karlsruhe. He himself studied mathematics, physics and electrical engineering at the University of Brno and received his doctorate.
In 1965, he accepted a call to become a full professor at the Technical University of Aachen in the chair of converter technology and electrical drives and took over the directorship. In his research, Wasserrab devoted himself to the emerging topic of semiconductor valves and made significant contributions to the limiting load of power diodes and thyristors.
Theodor Wasserrab received numerous recognitions. In 1976, for example, he received the VDE Ring of Honor from the Association of Electrical Engineers, and in 1982 he was made an honorary member of the German Society for Electric Road Traffic.