August Karolus

August Karolus 1930 with the Weiller's mirror wheel for scanning television images

August Karolus (born March 16, 1893 in rows (now part of Sinsheim ), † August 1, 1972 in Zollikon near Zurich ) was a German physicist . He gained importance as a pioneer of television technology in the 1920s. Karolus was a professor in Leipzig , Zurich and Freiburg . In 1924 he developed the Kerr-Karolus cell, named after him, for inertial light control, a further development of the Kerr cell based on the Kerr effect , which promoted electronic image transmission for television technology . He also made precision measurements of the speed of light .

Life

He was the eldest son of the farmer August Karolus, whose family had run a farm for many generations. He must have walked in rows with the sub-teacher Ludwig Link in the preschool. In the district town of Sinsheim he then attended the Grand Ducal Realschule for six years. He is said to have been very diligent and liked to do handicrafts. His first experiments began when he was about twelve years old, after he was born by his mother Emma. Kaiser had received an experiment kit for Christmas. For financial reasons, Karolus was initially unable to study at university, but he was able to attend the teachers' seminar in Ettlingen , where he stayed with relatives, and take the exams as a primary school teacher.

During the First World War he was drafted into military service. In 1917 he suffered a lung shot in Flanders , which was treated only superficially in the field hospital and which would presumably have led to Karolus' death had he not been found by accident by his brother and taken behind the front line for further treatment. He spent some time in a hospital in Hanover and then returned to Karlsruhe, where he graduated from high school in 1919 and then began to study physics and electrical engineering.

In early 1920 he received an assistant position at the University of Leipzig , where he received his doctorate in November 1921. In 1922 he accepted an assistant position with a teaching position for electronics at the Technical University of Stuttgart . In 1923 he returned to Leipzig. He researched remote transmission methods such as the light telephone and video telegraphy and carried out experiments with photocells, tube amplifiers for weak direct currents, tube transmitters, Braun tubes, etc. He improved the Kerr cell for controlling light fluctuations through voltage fluctuations and had it registered as a Kerr-Karolus cell under number 471720. In 1924 he presented a functional television set based on the Weiller's mirror wheel, which he continuously developed further with the Telefunken company . His successful attempts prompted Hans Bredow to promote television development at the Reichspost . With the Telefunken-Karolus picture telegraph , which exposed a light-sensitive film on the receiving side using the Kerr-Karolus cell, Karolus succeeded in transmitting the first picture from Berlin to Leipzig in 1925. Corresponding images were sent from Berlin to Vienna on April 2, 1926. On December 1, 1927, the Reichspost took up scheduled picture-telegraphy traffic between Berlin and Vienna using the Telefunken-Karolus system .

On September 1, 1926, he became an associate professor and head of the department for applied electricity theory at the University of Leipzig . In the following year, Karolus signed a general license agreement with Telefunken, AEG and Siemens. The so-called Siemens-Karolus-Telefunken system was used for image transmission between Berlin and Rome and Rio de Janeiro, and later also to Moscow, London and Japan.

Karolus' early developments were based initially on the inter-film process, in which the image signals on the receiving side were exposed on film and only then projected, which caused a time lag of around 85 seconds due to the exposure and development processes. His devices were complex, but with the addition of Weiller's mirror wheel they soon reached image sizes of up to 75 × 75 cm with 96 lines per image. At the radio exhibition in Berlin in 1928, Karolus competed with the system of the Hungarian physicist Dénes von Mihály , who only achieved an image size of 4 × 4 cm with 30 lines per image. Mihály's simple and inexpensive solution was convincing despite the poorer values, so that Mihály's 30-line image was the model for the first standard definition for television signals. In 1929 the Reichspost tested further developments from Telefunken-Karolus, Mihály, Fernseh AG and the Reichspostzentralamt.

On November 18, 1930, Karolus was awarded the Heinrich Hertz Medal in gold for his previous research. In the following years Karolus devoted himself particularly to the development of large-format television transmission systems. In November 1933 he signed the German professors' confession of Adolf Hitler . In 1935 he made a television board with a size of 4 × 5 meters and 40,000 pixels.

At the end of the Second World War, his institute in Leipzig was destroyed. In 1944 he married his long-time colleague Dr. Hilde Geest, with whom he made connections from his home town in Zurich after the end of the war, where he moved in 1946 to work as a consulting engineer at a company.

In 1955 he followed a professorship for applied physics at the Albert Ludwig University of Freiburg . There he devoted himself in particular to refinements in the measurement of the speed of light and quartz research. After the end of his teaching activities in 1962, he worked in his own laboratory from 1964.

Prof. Dr. August Karolus died at the age of almost 80 on August 1, 1972 in Zurich as a result of a heart attack. The Karolussche Villa, August-Karolus-Straße, and the Prof. Karolus Stadium are reminiscent of him in his hometown. In addition, the income from the August Karolus Foundation, founded by his widow in 1980, benefits those in need from among the ranks.

literature

• Walther Gerlach:  Karolus, August. In: New German Biography (NDB). Volume 11, Duncker & Humblot, Berlin 1977, ISBN 3-428-00192-3 , pp. 292-295 ( digitized version ).
• Hildegard Karolus: August Karolus: the beginnings of television in Germany in letters, documents and publications from his collaboration with Telefunken GmbH, Berlin 1923-1930 . Berlin u. a. VDE-Verlag, 1984 ISBN 3-8007-1372-1
• Horst Münz: August Karolus from the ranks near Sinsheim. TV technology pioneer . In: Kraichgau. Contributions to landscape and local research , volume 17, 2002, pp. 265–271
• Käthe Zimmermann-Ebert: Large district town Sinsheim - around the Steinsberg , Sinsheim 1990

Web links

• Literature by and about August Karolus in the catalog of the German National Library
• August Karolus in the professorial catalog of the University of Leipzig