This paper presents a modeling strategy to simulate the propagation of electrical perturbations induced by direct biasing of substrate junctions. Usually, this is done by identifying parasitic substrate devices such as bipolar transistors. However, mapping a topology with these bipolar transistors rapidly reaches its limits when several junctions are acting at the same time. In this paper, we propose a new modeling methodology of parasitic signals. It relies on a generalized model of p-n junctions and resistances that takes into account minority-carrier densities and gradients at the boundaries. We show that bipolar-transistor- and thyristor-related effects can be obtained from a network interconnection of these extended devices. Furthermore, we show that this modeling approach could be easily extended to simulate complex 3-D layouts. © 2009 IEEE.