INDUCED CURRENT IN AN INHOMOGENEOUS MEDIUM.

The Shockley-Ramo theorem is generalized to the case of the movement of electrical charges in an inhomogeneous medium. It is shown that the frequency spectrum of the induced current in a planar diode is determined by the change with coordinate of the ratio of the charge velocity to the dielectric constant of the medium. In the general case the induced current depends not only on the local values of the dielectric constant but also on its spatial derivatives.