Abstract: At least the opposing surface portions of the main electrodes of an excimer laser device are covered with materials which are resistive to chemical etching than nickel. The etching resistive material may be a platinum based alloy containing rhodium, ruthenium, iridium, or osmium; a nickel based alloy containing gold, platinum, rhodium, ruthenium, iridium, or osmium; or rhodium, ruthenium, iridium, or osmium. Thus, an excimer laser device is realized by which the lives of the electrodes and the laser gas are prolonged.

Abstract: A thyristor apparatus employing light-triggered thyristors comprises forward voltage detecting circuits (15) and a thyristor number detecting circuit (17). The forward voltage detecting circuits (15) detect forward voltages applied to light-triggered thyristors (13) to provide detected signals. The thyristor number detecting circuit (17) is responsive to the detected signals to cause light-triggered thyristors in a thyristor arm (U) to be turned on simultaneously in the case where the number of the light-triggered thyristors being supplied with forward voltages is one or more but not more than a predetermined number. Accordingly, if and when an overvoltage is applied to the thyristor arm (U), overvoltage suppressing elements (14) are prevented from being damaged even if partial commutation failure occurs in the light-triggered thyristors.

Abstract: An ozone generating apparatus is disclosed which comprises a power source device for feeding a rectangular waveform alternating current between the discharge electrodes of a discharge tube of an ozone generator. One or both of the output current and frequency of the power source device is controlled to overcome the disadvantages of the conventional ozone generating apparatus.

Abstract: An ozone generating apparatus comprises a rectangular waveform current feeding device for feeding rectangular waveform alternating current between discharge electrodes of a discharge tube of an ozone generator so that a constant current is fed by the rectangular waveform current feeding device during a half cycle period to the ozone generator which is equivalent to a capacitor. Accordingly, the voltage applied to the ozone generator has a waveform which changes in proportion to the time period. Such a voltage waveform is ideal for the ozone generator to improve the conventional ozone generating apparatus.

Abstract: An ozone generating apparatus is disclosed which comprises a power source device for feeding a rectangular waveform alternating current between the discharge electrodes of a discharge tube of an ozone generator. One or both of the output current and frequency of the power source device is controlled to overcome the disadvantages of the conventional ozone generating apparatus.