A '''matrix addressed''' display runs control signals only to the rows (lines) and columns of the display. (See also: [[Matrix#Technology|Display (mathematics)|matrix]]) For a screen size of ''m''×''n'' pixels, this scheme would requirerequires ''m''+''n'' control signals. In [[active matrix addressing]], some sort of capacitor (external to the cell proper) is used to maintain the state of the cell. [[Passive matrix addressing]] is used when the cell itself has a bistabilitybi-stability, so no external capacitor is needed. In some situations passive matrix addressing is used with the help of persistence of vision of the (usually human) eye so the cell need not be bistable. Persistence of vision is used in simpler, slower changing displays with relatively few picture elements such as clocks.
