Abstract: A discharge lamp lighting device which comprises a D.C. power supply, a load resonance circuit including an inductor, a capacitor and a discharge lamp; a polarity inverting circuit including at least a series circuit of first and second switching elements connected in parallel to the D.C. power supply for converting a D.C. power received from the D.C. power supply into an A.C. power to supply it to the load resonance circuit; and a control circuit for turning ON and OFF the switching elements alternately at a high frequency to alternately generate a first period during which an ON duration of the second switching element is longer than that of the first switching element and a second period during which the ON duration of the second switching element is shorter than that of the first switching element, to thereby apply a rectangular-shaped low frequency voltage to the discharge lamp. The control circuit superimposes a D.C.

Abstract: A power source device restricts any increase in a switching current to switching elements commonly used in two such different power source circuits as chopper and inverter circuits, while maintaining control independence of these circuits, by setting a period in which among currents flowing to the commonly used switching elements, the current flowing at least from one of the power source circuits has a polarity inverse to that of the current from at least the other power source circuit, to be in mutually cancelling directions.

Abstract: A power device includes at least two power conversion circuits respectively having at least one of switching elements, at least one of which switching elements in these conversion circuits being used in common as an element constituting the at least two different power conversion circuits, a control device providing at least a period in which at least one of currents flowing from at least one of the different power conversion circuits to the commonly used switching element has a polarity inverse to at least the other one of the currents flowing from at least the other one of the power conversion circuits, so as to cancel each other, and a unit for detecting the state of the respective conversion circuits. The operation of the switching elements is thereby made modifiable in accordance with a lowering in the resistance of a load of the device, and the withstand voltage of the elements can be prevented effectively from rising even upon any fluctuation in the load.

Abstract: A power source device is so arranged that one of switching elements forming a plurality of power conversion switching circuits which is used in common during each switching cycle is made to have a switching period in which mainly a current is taken up from a power source of first one of the switching circuits, the switching period being varied in a zone in which an input voltage is higher than a predetermined voltage in a cycle of input voltage waveform. Any distortion of input current waveform occurring around lower voltage period of commercial AC source is thereby reduced, in the power source device wherein the power conversion switching circuits employ commonly the switching elements.

Abstract: A power supply apparatus in which a series circuit of first and second switching elements not blocking their reverse-directional currents is connected in parallel to a series circuit of a D.C. power source and a capacitor, a primary winding of a transformer is connected between a junction point of the D.C. power source and capacitor and a junction point of the switching elements, a secondary winding of the transformer is connected to a load circuit, and a controller is provided for controlling ON and OFF operation of the switching elements to cause a switching frequency of the switching elements to be set higher than a resonance frequency of the capacitor and an inductance of the transformer and to cause a voltage across the capacitor to increase.

Abstract: An inverter device made detectable at a high speed and highly precisely a load voltage of all waves in one cycle, with an arrangement including a voltage detecting means having a capacitor and connected to a load which is connected through a switching means to a DC power source, means connected to the voltage detecting means for charging and discharging the capacitor, and means for maintaining, in a predetermined period in which a transient voltage upon every inversion of load voltage is generated, a capacitor voltage immediately before the predetermined period.

Abstract: A device for determining position coordinates of points on a surface, has a tablet containing plural number of equally spaced driver windings and plural number of equally spaced sense windings. Each driver winding has a pair of parallel conductors laid in X-direction, and each sense winding has a pair of parallel conductors laid in Y-direction. A current is generated in a cursor coil by the voltage induced from the current in a nearby situated driver winding. This current in the cursor coil induces a voltage in a nearby situated sense winding. The X-position of a sense winding in which a maximum voltage is induced, and the Y-position of a driver winding which induces a maximum voltage in the cursor coil, determine the position coordinates of the cursor on the tablet. Auxiliary sense windings are supplemented to the tablet. Induced voltages on these auxiliary sense windings determine the Y-position of the cursor regardless of its X-position, and reduce the overall time required for position determination.