Heinrich Barkhausen

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Heinrich Barkhausen
Stamps of Germany (DDR) 1981, MiNr 2603.jpg
Heinrich Barkhausen
Born December 2, 1881
Bremen
Died February 20, 1956
Nationality German
Fields physics
Alma mater Technical University of Munich
Known for Barkhausen effect

Heinrich Georg Barkhausen (December 2, 1881 – February 20, 1956), born at Bremen, was a German physicist.[1]

Born into a patrician family in Bremen, he showed interest in natural sciences from an early age. He studied at the Technical University of Munich (1901), TU Berlin (1902) and University of Munich (1903) and Berlin before obtaining a doctorate at the University of Göttingen in 1907.[1]

He became Professor for Electrical Engineering at the Technische Hochschule Dresden in 1911[1] at the age of 29, thus obtaining the world's first chair in this discipline.

He discovered in 1919 an effect named after him, the Barkhausen effect, which provided evidence for the magnetic domain theory of ferromagnetism.[1][2] When the magnetic field through a piece of ferromagnetic material like iron is changing, the magnetization of the material changes in a series of tiny discontinuous jumps, which can be heard as a series of clicks in a loudspeaker attached to a coil of wire around the iron. It was later determined that these jumps were caused by the movement of the magnetic domains in the iron, as the domain walls snap past defects in the crystal lattice. The energy lost in these dissipative events is responsible for the shape of the hysteresis curve of iron and other ferromagnets. This effect is widely used in research, and physics education as a simple experiment to demonstrate the reality of magnetic domains.

In 1920 with K. Kurz he invented the Barkhausen-Kurz oscillator,[2] the first vacuum tube electronic oscillator to use electron transit-time effects.[2][3] It was the first vacuum tube oscillator that could operate at ultrahigh frequency, up to 300 MHz,[3] and inspired later microwave transit-time tubes such as the klystron.[1]

In 1921 he derived the first mathematical conditions for oscillation in electrical circuits, now called the Barkhausen stability criterion. It is widely used today in the design of electronic oscillators, and general feedback amplifier circuits.

Publications[edit]

Four-volume textbook: Lehrbuch der Elektronenröhren, Elektronenröhren und ihre technischen Anwendungen.

References[edit]

  1. ^ a b c d e Daintith, John (2008). Biographical Encyclopedia of Scientists, 3rd Ed.. CRC Press. p. 46. ISBN 1420072714. 
  2. ^ a b c Petersen, J.K. (2002). Fiber Optics Illustrated Dictionary. CRC Press. p. 103. ISBN 084931349X. 
  3. ^ a b Sarkar, T. K.; Robert Mailloux; Arthur A. Oliner; M. Salazar-Palma; Dipak L. Sengupta (2006). History of Wireless. John Wiley & Sons. p. 114. ISBN 0471718149.