A cooktop is provided that includes heating elements which are combined to a heating zone; a power supply to generate a heating current that operates the heating elements; a switch to open and close a power circuit that includes the power supply and one of the heating elements; and a controller that determines a characteristic variable of the heating current, actuates the switch as a function of a selected power level to operate the heating zone, and activates, in a first operating state, two of the heating elements, which are combined to form the heating zone, in different phases of a heating period.