Hans Ferdinand Mayer

Hans Ferdinand Mayer
Pforzheim, Germany
Death date
Associated organizations
Fields of study
Nobel Prize in Physics


Hans Ferdinand Mayer was a German electrical engineer who developed numerous patents during a long career at Siemens and used this position to leak secret information to the British during World War II.

Mayer was born in Pforzheim, Germany, in 1895. He enlisted in World War I, but went on to study physics and mathematics at the Technische Hochschule in Stuttgart after being wounded in his leg during his first battle. He then enrolled at the University of Heidelberg, where he served as a research assistant for Philipp Lenard, who was awarded the Nobel Prize in physics in 1905. Mayer’s doctorate, which he earned in 1920, addressed the interaction of slow electrons with molecules. He continued to work with Lenard until 1922, when he joined Hause-Siemens.

In 1926, he published an article on equivalent circuits that extended Thevenin’s theorem, which holds that any set of voltage sources and resistors with two terminals equates to an ideal current source. Edward Lawry Norton described a similar transformation in a Bell Labs report the same year, and the theorem has become known as Norton’s Theorem or Mayer-Norton theorem.

Mayer spent the majority of his career at Siemens, where he became the director of its Research Laboratory in 1936. This position proved pivotal to his involvement in World War II. In November, 1939, he secretly disclosed what he knew about German warfare capacity, particularly regarding electronic warfare, to the British. His role as a technical advisor from Siemens allowed him to travel widely through Europe, giving him the opportunity to send a two-page report to the British embassy in Oslo, Norway, which would become known as the “Oslo Report.” By choice, Mayer’s identity as the “Oslo Person” remained hidden to the public until after his death.

The Gestapo arrested Mayer in 1943 for listening to British broadcasts and criticizing Nazi rule. He would have been executed but for the intervention of his former advisor, Lenard, who was an ardent anti-Semite and Nazi Party supporter. Mayer was sent to the Dachau concentration camp and four other prisons during the war.

After the war, Mayer moved to the United States for four years. With other German scientists, he participated in Operation Paperclip, and researched electronics at the Wright-Patterson Air Force Base in Dayton, Ohio, and became a professor of electrical engineering at Cornell University in 1947, where he wrote a standard textbook on pulse code modulation. He returned to Siemens in 1950.

He published twenty-five technical papers, secured over eighty patents, and won numerous awards for his research.

Further Reading

Don H. Johnson, "Scanning Our Past: Origins of the Equivalent Circuit Concept: The Voltage-Source Equivalent," 2002 Proceedings of the IEEE, Vol. 91, No. 5 (May 2003).