An ozone generator has two electrodes separated by a di-electric barrier connected to an alternating current power supply. The gap d3 between the electrodes is filled by air or oxygen. A fluid di-electric medium 'C3' passes through the gap d1 and functions as a di-electric barrier and as a coolant for electrode (7) and the corona discharge zone 4. The improvement is that: (a) a an intermediate electrode (5) is located between gap d3 and gap d1; (b) the electrode is manufactured from a material with a non-uniform structure; (c) the electrical resistance of the electrode (5) is very large (> 1000,000 ohm/cm) perpendicular to the vector of the electrical field; (d) the electrical resistance of the electrode (5) parallel to the vector of the electric field strength between electrodes 3 and 7 is equal to or less than the resistance of electrodes (6) and (8); (e) the perforations through intermediate electrode (5) manufactured with material of a specific electrical resistance are less than 0.0008 ohm x cm and that the material has a heat conductivity of greater than 0.1 cal./(cm x sec. x degree).
