Abstract: Large area glow discharge plasma can be used as transparent and high conductive electrodes in electro – optical switches that considerably extended the switch aperture. To investigate problems related to this technology we designed and constructed an 80mm 80mm electro ?optical switch with plasma electrodes. This paper describes the Pockels cell configuration, the discharge electrode geometries, the discharge circuit and parameters. Experimentally, the effect of preionization and gas pressure on discharge performance is observed.