ÐFor the relative amplitude of the random telegraph signal noise (RTS) in a MOS transistor DG/G=DI/I=1/N= qgm/WlCoxI often holds with N the total number of free carriers. Here, strong deviations from this simple behavior will be explained in terms of strategic (high ®eld region) or less strategic trap positions (low ®eld region) in a non-uniform channel ignoring mobility modulation. Cal- culations show that in a channel with N=103 and a nonuniform current distribution, the relative RTS amplitude can vary between 10 ÿ5 and 10 ÿ2. The analytical expressions to calculate the relative ampli- tude of the RTS noise for two and four terminal geometries are presented. The levelling o¿ in the 1/N dependence for extremely low N in the subthreshold region is explained via the solution of the Poisson equation showing that this phenomenon occurs for QdepletionrQinversion even in a uniform channel.