Following Hooge’s suggestion [F. N. Hooge, Phys. Lett. A29, 139 (1969)] that 1/fnoise follows a simple empirical law involving a parameter &agr;H, with the noise caused by mobility fluctuations, we examine the mobility fluctuations produced by dislocations in semiconductors, viz. produced by carrier trapping levels in a linear array. In the present contribution we analyze the fluctuations of trapped carriers, where the trapping is dominated by the cylindrical space charge regions around the dislocations. The corresponding mobility fluctuations are evaluated in Part IV of the series.