In this paper, the dynamics of a dc-ac resonant self-oscillating LC series inverter is analyzed from the point of view of piecewise smooth dynamical systems. The system under study is defined by two symmetric configurations and its bifurcation analysis is performed in a one dimensional parameter space. This analysis reveals that a non smooth transition takes place between two strongly different dynamical behaviors. The first one is an oscillating regime, which is the one used in applications and it involves a repetitive switching sequence between the system configurations. This behavior is exhibited whenever the open loop equilibrium corresponding to the system configurations are foci. The second one is a non desired stationary regime corresponding to the equilibrium points of node type whose stable manifolds preclude the appearance of oscillations.