After attending the gymnasium and engineering college in his native city of Bremen, Barkhausen gained his PhD in Göttingen and in 1911 became professor of electrical engineering in Dresden. Here he formulated the basic equations governing the coefficients of the amplifier valve.

In 1919 he discovered the Barkhausen effect, observing that a slow continuous increase in the magnetic field applied to a ferromagnetic material gave rise to discontinuous leaps in magnetization, which could be heard as distinct clicking sounds through a loudspeaker. This effect is caused by domains of elementary magnets changing direction or size as the field increases.

In 1920, with K. Kurz he developed an ultrahighfrequency oscillator, which became the forerunner of microwave-technology developments. After World War II he returned to Dresden to aid the reconstruction of his Institute of High-Frequency Electron-Tube Technology, which had been destroyed by bombing, and remained there until his death.