This study examines the appearance of self-modulation in nonlinear electrical circuits presenting the jump resonance phenomenon and variable inertial damping. The oscillations envelope is a slow forced oscillation, periodic or non-periodic, its character being determined by the environmental influence on the damping factor. The results of this experimental study were obtained by numerical simulation and experiment and confirm the initial theoretical considerations. Copyright (c) 2012 John Wiley & Sons, Ltd.