The ratio of drive frequency f
to capacitance C
of the barrier layer on electrodes was investigated to generate a glow-like barrier discharge in air at atmospheric pressure. The uniformity of the discharge was estimated by observing the optical emission from the discharge through a transparent electrode and a glass plate used as the barrier layer. The impedance of the barrier layer 1/(2πfC
) was kept at 12.3kΩ and the drive frequency f
was varied from 33.3kHz to 100kHz. Air and nitrogen were both used as the discharge gas. The discharge contained bright spots generated by self-organization. The distribution and diameter of the bright spots were affected by f/C
and the species of discharge gas used. The lager f/C
was chosen, the more homogeneous the discharge that appeared when nitrogen served as the discharge gas. In contrast, the optimum value of the f/C
that allowd homogeneous discharge occurred when air was used. It seems that the bright spots appear more readily when either the discharge cycle is shorter than the lifetime of the active species or when the effects of discharge current regulation by the barrier layer lessen.