The one‐carrier injection current‐voltage characteristics for insulators having two equal metal contacts and containing traps are computed, together with the free‐carrier zero‐bias spatial distributions, for extrinsic semiconductors. It is shown that the overlap of the contacts may give rise to trap‐filled‐limit characteristics governed by a power law. The steepness of these characteristics proves to be less than that predicted by Lampert and Edelman. The shallow‐trap square‐law characteristic may be entirely replaced by an overlap‐determined Ohm's law characteristic. The overlap sometimes fails to be removed through impurity conduction.