Heinrich Johann Welker (September 9, 1912 in Ingolstadt – December 25, 1981 in Erlangen) was a German theoretical and applied physicist who invented the "transistron", a form of transistor made at Westinghouse independently of the first successful transistor made at Bell Laboratories. He did fundamental work in III-V compound semiconductors, and paved the way for microwave semiconductor elements and laser diodes.
Biography and important work 
Starting in 1931, Welker studied at the University of Munich under Arnold Sommerfeld, and was granted a Ph.D. in 1936. The book Electrodynamics - Lectures on Theoretical Physics Volume III by Sommerfeld was based on lecture notes prepared by Welker during the winter semester of 1933/1934. Welker was granted his Habilitation under Sommerfeld in 1939.
During the war years, 1940 to 1945, Welker worked at Luftfunkforschungs Institut in Oberpfaffenhofen, but still maintained association (1942 to 1944) with the physicochemical institute of Klaus Clusius at the University of Munich. After the war, 1947 – 1951, he took a job at the Westinghouse subsidiary in Paris, Compagnie des Freins et Signaux Westinghouse. From 1951 to 1961, Welker headed of the solid-state physics department of Siemens-Schuckertwerke, in Erlangen, where he developed the new, III-V compounds, to replace silicon semiconductors. His work resulted in large-scale use of galvanomagnetic and optoelectronic effects, as well as new switching circuits in microelectronics. Welker and his department paved the way for microwave semiconductors and laser diodes. He was the director of the Erlangen Siemens-Schuckertwerke research laboratory from 1961 to 1969. From 1969, until he retired in 1977, Welker was director of all the company’s research laboratories.
While at the Westinghouse subsidiary in Paris, Welker and German physicist Herbert F. Mataré, just months after Bell laboratory scientists announce the demonstration of a point contact transistor in 1948, applied for a patent on the same type of device on August 13, 1948. On 18 May 1949, this European invention coined as the "Le Transistron" or the "French transistor" was presented to the public. This development was an outgrowth of work done by the two independently in Germany in programs to develop German radar. The French patent was granted in 1952.
Selected Literature 
- Sommerfeld, A.; Welker, H. (1938). "Künstliche Grenzbedingungen beim Keplerproblem". Annalen der Physik 424: 56. Bibcode:1938AnP...424...56S. doi:10.1002/andp.19384240109. as cited in Sommerfeld Bibliography
- Arnold Sommerfeld and Heinrich Welker Über ein elektronentheoretisches Modell des Supraleiters. Mitteilung über die Arbeit., Sitzungsberichte der mathematisch-naturwissenschaftlichen Klasse der Bayerischen Akademie der Wissenschaften zu München page 5 (1938) as cited in Sommerfeld Bibliography
- Michael Riordan (November 2005). "How Europe Missed The Transistor". IEEE Spectrum 42 (11): 52–57. doi:10.1109/MSPEC.2005.1526906.
- FR 1010427 H. F. Mataré/H. Welker/Westinghouse: „Nouveau sytème cristallin à plusieurs électrodes réalisant des effects de relais électroniques“ filed on August 13, 1948
- US 2673948 H. F. Mataré/H. Welker/Westinghouse: „Crystal device for controlling electric currents by means of a solid semiconductor“ french priority date August 13, 1948
- Mehra, Jagdish and Helmut Rechenberg The Historical Development of Quantum Theory. Volume 6 The Completion of Quantum Mechanics 1926-1941. Part 2 The Conceptual Completion and the Extension of Quantum Mechanics 1932-1941. Epilogue: Aspects of the Further Development of Quantum Theory 1942-1999 (Springer, 2001) ISBN 0-387-95086-9
- Sommerfeld, Arnold, translated from the German by Edward G. Ramberg Electrodynamics - Lectures on Theoretical Physics Volume III (Academic Press, 1964)
- Mathematics Genealogy Project: Welker Dissertation title: Allgemeine Koordinaten und Bedingungsgleichungen in der Wellenmechanik. Welker Dissertation.
- Sommerfeld, 1964, p. viii.
- A scribe took class notes during lectures and wrote them up for the professor, and, sometimes, the student library. While this task required considerable effort and skill, as well as understanding of the subject matter, it also afforded the scribe with close and frequent contact with the professor – a considerable intellectual benefit to the capable student. This task also fell under the purview of assistants to professors.
- Mehra, Volume 6, Part 2, 2001, p. 868.
- How Europe Missed the Transistor
- Siemans Archive: Welker
- FR 1010427 H. F. Mataré / H. Welker / Westinghouse: "Nouveau sytème cristallin à plusieurs électrodes réalisant des relais de effects électroniques" filed on August 13, 1948
- US 2673948 H. F. Mataré / H. Welker / Westinghouse, "Crystal device for controlling electric currents by means of a solid semiconductor" French priority August 13, 1948
- Armand Van Dormael:The "French" transistor.Proceedings of the 2004 IEEE Conference on the History of Electronics, Bletchley Park, June 2004.
- An Inventor of the Transistor Has His Moment
- MPower Solutions, Ltd.
- The Industry Era: 1947
- Welker Award - Heinrich Welker Memorial Award, Siemens AG. Award recipients are selected by the International Symposium on Compound Semiconductors Award Committee.