Abstract
Space‐charge‐limited currents (SCLC) in insulators with a nonuniform spatial distribution of traps have been discussed. General solutions for SCLC controlled by shallow or ``deep'' traps are derived for distribution of traps in energy and in space of the form f(E) g(x). In general data on the spatial distribution of traps cannot be obtained from the current‐voltage or current‐temperature dependences.