Abstract: An electric power supply apparatus comprises a traveling-wave tube 15 exhibiting partial negative-resistance characteristics and a voltage stabilizing circuit for controlling a voltage control element 12 using an error amplifier 16 and a switch and for supplying stable power to the traveling-wave tube 15. In the apparatus, whether a traveling-wave tube 15 is in positive-resistance operation or negative-resistance operation is detected. In the negative-resistance operation, the control using the error amplifier 16 and the switch S1 is rendered ineffective.

Abstract: A high voltage DC/DC converter including a voltage resonance switching circuit formed by a coreless transformer, a GTO thyristor switching element connected between the primary winding of the transformer and a D.C. source, and a voltage resonance capacitor connected in parallel to the switching element. A rectifier circuit is connected to the secondary winding of the transformer to rectify an output current from the transformer circuit. The resonance frequency of the parallel resonance circuit made of the resonance capacitor and the coreless transformer is selected to be the frequency of that component of the current supplied to the circuit through the switching element, which has a greater amplitude than any other component of the current (including the fundamental frequency and other harmonic).

Abstract: Digital radiography apparatus uses a resonance-type high frequency inverter having a main switch in series with an auxiliary switch. An X-ray tube receives the pulsed power from the high frequency inverter, after voltage ampliflication and rectification, emitting pulsed X-rays to a patient. A TV camera obtains X-ray transmission images of the patient, and an image processor generates a visual diagnostic image by subtracting one X-ray transmission image from another. The high frequency inverter circuit is controlled synchronously with the processing operation of the image processor.

Abstract: A resonance inverter includes a DC power source, a resonance capacitor, an inductor, and a plurality of semiconductor switches. The resonance capacitor and inductor form a parallel resonant circuit. The inverter further includes control means for detecting a peak value of the voltage across the resonance capacitor, and for alternately conducting said semiconductor switches with a certain lead phase with respect to the peak point of the capacitor terminal voltage.

Abstract: A main switch consisting of a switching transistor and a current transformer is triggered at the leading edge of a main switch drive pulse. The switching transistor then starts a positive feedback operation through the current transformer and is turned on at high speed. Upon activation of the switching transistor, the magnetic core of the current transformer is saturated by the switching transistor emitter current flowing in the current transformer. Magnetic saturation of the core turns off the switching transistor with the magnetic energy stored in the current transformer. The main switch drive pulse falls after the switching transistor is turned off.

Abstract: An apparatus for supplying high voltage pulsed direct current to an X-ray tube includes a transformer, a high frequency inverter circuit and a nonlinear feedback loop. The invention uses the high frequency inverter connected in series with a DC power supply source and the primary winding of the transformer in order to generate high voltage, high frequency AC in the secondary winding. A rectifier connected to the secondary winding supplies high voltage pulsed DC to the X-ray tube. A detector, such as a voltage divider, detects the voltage supplied to the X-ray tube and supplies a representation of it to a nonlinear feedback circuit connected between the detector and the high frequency inverter. The inverter circuit includes at least one switch generated by electrical pulses.

Abstract: A switching power supply has a saturable transformer provided with first to fourth windings. The first winding is inserted in series in a first path from a DC power source to a primary winding of a power transmitting transformer. A main switch is inserted in series in the first path and controlled by an output of the second winding. The operation of the main switch is positively fed back through the saturable transformer. A capacitor is connected in parallel to a series circuit consisting of the main switch and the first winding. An auxiliary source for generating a predetermined direct current output is provided to drive the third winding by a polarity opposite to that of the first winding. An auxiliary switch is inserted in series in a second path from the auxiliary source to the third winding and controlled by an output of the fourth winding. The operation of the auxiliary switch is positively fed back through the saturable transformer.

Abstract: The dissipation of the filament power of an X-ray tube is controlled by a heating circuit including a voltage resonance type DC-to-DC converter and a filament current detector/controller. The DC-to-DC converter is comprised of a switch, a capacitor, a damper diode and a transformer. These circuit elements constitute a voltage resonance type switch. A DC voltage is interrupted and applied to the primary winding of the transformer. The AC voltage is induced to the secondary winding of the transformer, thereby heating the filament of the X-ray tube. In accordance with the load curve of the X-ray tube, the filament heating voltage can be controlled within a control range defined by the resonant conditions of the switch.

Abstract: A single ended, separately driven, resonant DC-DC converter including a transformer, a capacitor connected in parallel with a primary winding of the transformer, a switching transistor connected between one end of the primary winding of the transformer and one end of a DC power source, and a blocking oscillating circuit for driving the switching transistor. The blocking oscillating circuit is directly driven by the DC power source and contains circuits for properly setting a pulse width and a pulse stop period of output pulses from the blocking oscillating circuit.

Abstract: A high frequency switching circuit comprised of a single-ended switching circuit, rectifying-smoothing circuit and magnetic amplifier which is connected between said single-ended switching circuit and rectifying-smoothing circuit. The magnetic amplifier includes a saturable reactor which has a coercive force Hc of 0.6 Oe or above and a rectangular ratio Br/Bs of 80% or below at an operating frequency of 20 kHz. The saturable reactor is prepared from an amorphous magnetic alloy having a composition of(Co.sub.1-a-b-c Fe.sub.a Ni.sub.b M.sub.c).sub.1-d X.sub.dwhere:M=one element selected from a group consisting of the elements of Nb, Cr, Mo, V, Ta, Ti, Zr and WX=B or a compound of B and Si in which the content of Si is set at 25 atomic % or less0.04.ltoreq.a.ltoreq.0.150.ltoreq.b.ltoreq.0.100.005.ltoreq.c.ltoreq.0.100.15.ltoreq.d.ltoreq.0.30.

Abstract: A single-ended switching circuit is constituted by a primary winding of a transformer, a switching circuit connected between the primary winding and a DC power supply and on-off operated with a predetermined cycle and also with a predetermined "on" period and a resonance capacitor connected in parallel with the primary winding. A magnetic amplifier, a rectifying element and a choke coil are connected in series between a secondary side circuit of the transformer and the load. The magnetic amplifier includes a saturable reactor which is held saturated during a half cycle of the voltage induced in a secondary winding of the transformer and remains unsaturated during the other half cycle of the voltage.

Abstract: A switching element is connected between a power supply and the primary winding of a transformer, and it is on-off controlled with a predetermined cycle and with a predetermined conducting period. The secondary winding of the transformer is connected to a parallel circuit of a filtering capacitor and a load via a rectifier diode and a choke coil. A closed circuit, to which the reflux current of the choke coil flows through the parallel circuit of the filtering capacitor and load, is formed by a reflux diode.

Abstract: A switching element, a transformer having a primary winding connected through said switching element to a DC power supply and a resonance capacitor connected in parallel with the primary winding of said transformer constitute a single-ended switching circuit. A magnetic amplifier is connected between the secondary side circuit of the transformer of the single-ended switching circuit and a rectifying/smoothing circuit, thus forming a high frequency switching circuit.

Abstract: A series circuit of a transistor serving as a switching element and an input power supply is connected in parallel with the primary side inductor of a transformer. A resonance capacitor and a damping diode are connected in parallel with the transistor. When the transistor is turned on in response to a pulse signal supplied from a pulse generator, the current from a DC power supply is supplied to the transformer. At the same time, a commutating diode is turned on to supply the output current from the transformer to a load resistor.

Abstract: A high frequency switching circuit in which, to reduce power dissipation of a switching element, the characteristic impedance defined by the inductance of a transformer connected in series with the switching element and the capacitance of a capacitor connected in parallel with the switching element, the ratio of the input voltage and an output voltage, and the ratio of ON time and a switching period T of the switching element are each selected within a given range. Alternatively, a ratio pertaining to a leakage inductance of the transformer and an inductance of an additional inductor, and a ratio pertaining to the output and input voltages are selected to satisfy a predetermined relation and the characteristic impedance is selected within a given range.

Abstract: The elastic surface wave device comprises a piezoelectric substrate having a dielectric constant of .epsilon..sub.2, a dielectric film having a dielectric constant of .epsilon..sub.1 and a thickness of h, and deposited on the piezoelectric substrate, and an inter-digital type input-ouput transducer formed on the dielectric film. The ratio of the dielectric constants .epsilon..sub.1 /.epsilon..sub.2, and a function 2.pi./.lambda..multidot.h proportioned to the thickness of the dielectric film are selected to satisfy a condition established in a frustum shaped region bounded by coordinate points P (.epsilon..sub.1 /.epsilon..sub.2 = 1/5,(2.pi./.lambda.).multidot.h = 0.1), Q(.epsilon..sub.1 /.epsilon..sub.2 = 1/5,(2.pi./.lambda.).multidot.h = 0.00016), R(.epsilon..sub.1 /.epsilon..sub.2 = 1/500,(2.pi./.lambda.).multidot.h = 0.0004), and S(.epsilon..sub.1 /.epsilon..sub.2 = 1/500, (2.pi./.lambda.).multidot.h = 0.006) on a graph wherein the ratio .epsilon..sub.1 /.epsilon..sub.

Abstract: A surface wave apparatus which comprises an insulation substrate having a smooth surface; a surface wave conversion interdigitated electrode evaporated on the smooth surface of the insulating substrate; a piezoelectric plate, on the smooth surface of which the insulation substrate is mounted at a prescribed space in contact with the electricity-surface wave conversion interdigitated electrode; an insulation liquid layer provided between the smooth surface of the piezoelectric plate and the electricity-surface wave conversion interdigitated electrode as well as between the smooth surface of the piezoelectric plate and the smooth surface of the insulation substrate.

Abstract: An elastic surface wave device comprises a piezoelectric body and interdigital type electric signal-surface wave conversion conductors formed one at each end portion of one surface of the piezoelectric body. A groove elongated in a surface wave propagation direction is provided in a surface opposite to the surface on which the conversion conductors are formed.

Abstract: An elastic surface wave apparatus, wherein transmission and reception electrode pairs for conversion of electric signals into elastic surface waves are spatially disposed so as to cause said surface waves to be propagated over the X-Z axis surface of a Y-cut lithium niobate (LiNbO.sub.3) piezoelectric element in a direction inclined 0.5 to 7 degrees relative to the Z axis.