Abstract: A gas laser device includes a high frequency power source for generating a high frequency output voltage and a pair of electrodes positioned sandwiching a discharge gap through which laser gas circulates. The pair of the electrodes are connected to the high frequency power source for applying the high frequency output voltage across the electrodes to achieve discharge in the discharge gap and to thereby generate laser light. Each of the electrodes includes an electrode element, a capacity coupling control element provided on either side of the electrode element, and a dielectric shell. The dielectric shell surrounds the electrode element and the capacity coupling control element, therefore the discharge occurs between the dielectric shells of a pair of the electrodes. The dielectric constant of the capacity coupling control means is lower than that of the dielectric shell.

Abstract: A gas laser device, including an a.c. power source for generating a.c. output voltage and a pair of electrodes positioned sandwiching discharge gap through which laser gas circulates. The pair of electrodes are connected to the a.c. power source for applying the a.c. voltage across the electrodes to achieve discharge in the discharge gap such as to create a positive column region and boundary layer regions, thereby to generate laser light. The positive column region is created in the discharge gap and a.c. power injected therein contributes to laser excitation. The boundary layer regions is created in a vicinity of one of the pair of electrodes, respectively and a.c. power injected therein does not contribute to laser excitation. A frequency of the a.c. power source is set to at least 700 kHz and an a.c. output voltage of the a.c. power source is set at a level such that a voltage in the positive column region is larger than a burden voltage in the boundary layer regions.

Abstract: A vacuum switch having two main electrodes encased in a vacuum vessel to be operable in opening and closing the main electrodes, is provided with a contact piece made of a copper-chromium alloy secured or formed on at least one of the main electrodes. The operational property of the main electrodes is substantially improved by flowing and interrupting an electric current of a predetermined current density for a number of times through the two main electrodes for improving surface condition of the contact piece by forming a recrystallized layer over the outer surface of the contact piece.

Abstract: A DC interrupter unit as provided between a DC power source unit and a load unit. The DC interrupter unit includes a DC interrupter section having at least one interrupter to interrupt a DC current and a saturable reactor connected between the interrupter section and one terminal of the load unit. The interrupter unit further includes a series circuit having a resistor and capacitor in series, the series circuit being connected between the junction of the interrupter section and the saturable reactor and the other terminal of the load unit.

Abstract: A direct current interrupter comprising a plurality of two-point interrupter units each including a pair of interrupting portions. The interrupting portions of the interrupter units are arranged at regular angular intervals on a circle with the axial line of the interrupter as its center and arranged parallel to the axial line. An input terminal is provided to supply shunted current to one interrupting portion of each interrupter unit. An output terminal is provided to receive the shunted current from the other interrupting portion of each interrupter unit. A first common connecting portion and a second common connecting portion near the axial line. The main current flows through a conductor line from the main current input terminal to the first common connecting portion and shunted.