Variable resistor device for display device and method of controlling variable resistance using the same

A display device includes a display panel on which a pixel electrode and a common electrode are patterned, and a variable resistor configured to vary a common voltage applied to the common electrode. The variable resistor includes a variable resistance control unit configured to control resistances between resistance terminals that are electrically connected to one another. The variable resistance control unit includes a crown unit, a crown axis combined with the crown unit and configured to guide up/down movement of the crown unit, a first motion variable unit combined with the crown axis, a second motion variable unit selectively combined with the first motion variable unit and configured to vary a variable resistance due to rotary power transmitted from the crown unit, and a housing unit configured to accommodate the crown unit, the crown axis, the first motion variable unit, and the second motion variable unit