Instead, sub-units of the display (typically, rows or columns for a dot matrix display or individual characters for a character orientated display, occasionally individual display elements) are multiplexed, that is, driven one at a time, but the electronics and the persistence of vision combine to make the viewer believe the entire display is continuously active.In senven segment displays the various segments of each character are connected in a two-dimensional matrix and will only illuminate if both the 'row' and 'column' lines of the matrix are at the correct electrical potential. In the technique of multiplexing the entire display is not driven at one time.