Fysici
Heinrich
Georg Barkhausen (1881-1956) |
| German
physicist who discovered the Barkhausen effect, a principle concerning
changes in the magnetic properties of metal. Barkhausen attended the
universities of Munich and Berlin before earning his doctorate in
1907 from Göttingen. After working for the Siemens & Halske
laboratories in Berlin, he accepted the world's first professorship
in the communications branch of electrical engineering, at the Technical
Academy in Dresden (1911). There he worked on theories of spontaneous
oscillation and nonlinear switching elements and formulated electron-tube
coefficients that are still in use. He also experimented with acoustics,
proposing methods for the subjective measurement of loudness. His
work in acoustics and magnetism led to the discovery in 1919 of the
Barkhausen effect, which provided evidence that magnetization affects
whole domains of a ferromagnetic material, rather than individual
atoms alone. In 1920 Barkhausen developed, with Karl Kurz, the Barkhausen-Kurz
oscillator for ultrahigh frequencies (a forerunner of the microwave
tube), which led to the understanding of the principle of velocity
modulation. He is also known for experiments on shortwave radio transmissions. © 2001 Britannica.com Inc. |
 |
