One of the main features of ferroresonance behavior is its different responses with the same parameter values depending on initial conditions. In this paper a simple ferroresonance circuit has been studied via mathematic software Matlab. Different parameter effects on ferroresonance behavior especially different initial conditions have been studied. Core losses are nonlinear so it has been represented with a nonlinear equation and implemented in calculations. Domains of period-1 ferroresonance occurrence has been obtained in a space of parameters