The wall voltage is first expressed by a Fourier series

and an equation of electron motion in AC plasma display cell is then established. The expression of firing condition

dielectric constant and electrical conductivity of AC plasma display cell can be derived from the equation’s solution. Computed results show that the dielectric constant of a cell increases when the cell discharges most intensively

a new explanation why the cell capacitance increases at the most intensive discharges. It is theoretically proved that the discharge of the cell obeys Paschen’s law. Experimental and theoretical values are in good agreement.