The steady-state responses of the buck converter are determined by means of computer simulation and presented in a form of one-parameter bifurcation diagrams and two-parameter bifurcation diagrams. It is shown that analysed converter can be driven into chaos through a process of period doublings for each of the three chosen bifurcation parameters: the input voltage, the load inductance and the period of the external sawtooth ramp voltage. The results of simulation agree well with those obtained by measurements carried out on a physical model of the circuit.