Abstract: Illumination sources, each including at least one light emitting diode, are connected either in series or in parallel by a switching circuit, depending upon an applied input voltage. The switching circuit switches the illumination sources from series- to parallel-connection, or vice versa, when the applied input voltage crosses a threshold value in traversing the operating range of applied input voltages. Because the light emitting diodes within the illumination sources are switched from series to parallel connection at a defined kickover point, the voltage-luminance characteristic changes on opposite sides of the kickover point. The resulting overall voltage-luminance characteristic has greater variability in luminance across the entire operating range of applied input voltages, and luminance-variance is not limited to only a portion of the operating range.