Abstract: An electrodeless gas discharge light assembly includes a lamp base (12) having a pair of light-transmitting lenses (14, 16) supported in axially opposed relation to one another. An electrodeless gas discharge light source (28) is mounted between the lenses (14, 16) and comprises a generally flat spiral induction coil (30) sandwiched between a pair of generally flat, planar envelopes (32, 34) in which an ionizable gas (46) is contained. Energizing the coil (30) inductively induces discharge illumination of the gas (46) causing light to be emitted in axially opposite directions through the lenses (14, 16) without obstruction by the coil (30).

Abstract: A fluorescent illuminating apparatus includes a translucent housing with a chamber within which a fluorescent medium is supported and electrical connections configured to provide an electrical potential across the chamber. An inductive-resistive structure is fixed sufficiently proximate to the housing to induce fluorescence in the fluorescent medium when an electric current is passed through the inductive-resistive structure while an electric potential is applied across the electrical connections of the housing. Preferred inductive structures for use with the present invention include elongate tape structures having a substrate with a conductive-resistive coating. A method of inducing fluorescence comprises passing a current through an inductive structure which is adjacent a fluorescing medium in an amount sufficient to induce fluorescent in the fluorescing medium in the presence of an electrical potential imposed on the fluorescing medium.

Abstract: The invention relates to a circuit arrangement for operating at least one electrodeless discharge lams (LP1) having at least one voltage input (j10, j11) for supplying voltage to the circuit arrangement and electrical terminals (j12, j13) for at least one electrodeless discharge lamp (LP1). The circuit arrangement has supervisory means which ascertain the presence or the absence of the at least one electrodeless discharge lamp (LP1) at the electrical terminals (j12, j13) and enable the provision of the ignition or operating voltage for the at least one electrodeless discharge lamp (LP1) only when the at least one electrodeless discharge lamp (LP1) is connected to the electrical terminals (j12, j13).

Abstract: An electric lamp assembly includes an electrodeless lamp, including an electrodeless lamp envelope, a transformer core disposed in proximity to the lamp envelope and an input winding disposed on the transformer core. The lamp envelope preferably comprises a closed-loop, tubular lamp envelope, and the transformer is preferably disposed around the lamp envelope. The electrodeless lamp envelope encloses a fill material for supporting a low pressure discharge. The electrodeless lamp further includes an amalgam located within the lamp envelope. The input winding receives radio frequency energy which produces a low pressure discharge in the lamp envelope. The electrodeless lamp includes a thermal bridge between the transformer core and the amalgam, so that the amalgam is heated by the transformer core during operation.

Abstract: A circuit arrangement for igniting and operating an electrodeless discharge lamp provided with a half-bridge commutator having two switching elements each having an emitter electrode and a control electrode and a parasitic capacitance in between. Each switching element is alternately switched to a conducting state by means of a resonant control circuit. The resonant control circuit is coupled to an oscillator by way of a transformer. The resonant circuit is provided with a capacitor which forms a part of the oscillator.

Abstract: An electrodeless high intensity discharge lamp with a lamp fill material including gallium iodide has been found to be more efficient in generating light in general, and more efficient in generating blue light. The very small size of the lamp, in combination with the high intensity in a relatively narrow blue spectral range make the lamp particularly useful in supplying blue light to a fiber optic. The relative efficiency of the lamp increases its value. In combination, the lamp provides a useful, efficient source of blue light as an input source for optical fiber, and other systems for medical and other processes using blue light as a process element.

Abstract: The discharge lamp comprises a piezotransformer and at least one of the lamp electrodes comprises a secondary side of the piezotransformer. Since the piezotransformer functions as a lamp electrode, as a ballast choke and as a transformer, the discharge lamp can be operated by means of a relatively simple and cheap ballast circuit.

Abstract: The invention relates to a discharge lamp whose discharge vessel (1) is pided with a light-transmitting, electrically conductive layer (4) in order to improve the electromagnetic compatibility of the lamp when it is operated from an electronic operating unit. The light-transmitting, electrically conductive layer (4) is advantageously connected to the circuitry-internal ground potential of the operating unit.

Abstract: A light-transmissive discharge vessel (1) encloses a discharge space (10) which contains an ionizable filling comprising an evaporable component. The low-pressure discharge lamp is also provided with coil for maintaining an electric discharge in the discharge space, and with a carrier (3) with a resilient body (30) and an open holder (31). The resilient body (30) is clamped inside a tube (14) which communicates with the discharge space (10). The holder (31) is clamped inside the resilient body (30). In the absence of the holder (31), the resilient body (30) can be inserted in a released state in the tube (14) with play (x).

Abstract: A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management.

Abstract: An rf capacitively-coupled electrodeless light source is provided. The light source comprises a hollow, elongated chamber and at least one center conductor disposed within the hollow, elongated chamber. A portion of each center conductor extends beyond the hollow, elongated chamber. At least one gas capable of forming an electronically excited molecular state is contained within each center conductor. An electrical coupler is positioned concentric to the hollow, elongated chamber and the electrical coupler surrounds the portion of each center conductor that extends beyond the hollow, elongated chamber. A rf-power supply is positioned in an operable relationship to the electrical coupler and an impedance matching network is positioned in an operable relationship to the rf power supply and the electrical coupler.

Abstract: In some embodiments, a light bulb for an electrodeless discharge lamp has a protuberance such that the cold spot of the bulb is located in the protuberance. The protuberance is spaced from the induction coil of the lamp so as to be easily accessible. Hence the cold spot temperature is easy to measure and control. In some embodiments, heat sinks are provided to cool the light bulb. An active control element including a Peltier element is provided to control the cold spot temperature.

Abstract: AC voltage is applied to a resonant unit provided with an inductor and a capacitor AC current is supplied to a discharge tube connected to one of the inductor and the capacitor according to the switching operation of the two power semiconductor elements connected in a bridge manner. The resonant unit and first and second voltage drop units are connected in series between I/O terminals of the bridge and the voltages of the first and the second voltage drop units are applied as signals of opposite phases to control terminals of the two power semiconductor elements.

Abstract: A light assembly (10) for a vehicle includes a housing (12) having a light-transmissive cover (18) and an RF emission gas discharge light source (22) provided as a self-contained module mountable in the housing (12). The module (22) includes an envelope (24) filled with an RF excitable gas (27) and an RF induction coil (28). The envelope (24) and coil (28) are fixed in working relation to one another in a common base (40). The base (40) also supports an electrical connector (32) that leads to the coil (28) and that mates with a corresponding connector (34) leading from the vehicle power supply (38). The module (22) and housing (12) have mutually connectable mounting portions (48, 50) for mounting the module (22) on the housing (12).

Abstract: A fluorescent lamp operating apparatus is used for operating a fluorescent lamp, which includes a glass tube coated with a phosphor and has at least mercury sealed therein, by generating an electric field in a direction from an inner surface of the glass tube toward a center of the glass tube. The operating apparatus, for example, includes: a ballast circuit connected to the fluorescent lamp for starting the fluorescent lamp; a potential application member disposed so as to at least partially surround discharge plasma generated in the fluorescent lamp; and a potential application circuit for applying a potential to the potential application member. In such a case, the potential application circuit applies a potential to the potential application member which is higher than the potential of the discharge plasma.

Abstract: An electronic ballast having an RF resonant inverter and RF feedback from the inverter which provides power factor correction. The feedback is provided by a capacitor coupled between an RF resonant tank circuit of the resonant inverter and a low frequency point in the ballast. Such feedback integrates the power factor correction stage with the RF resonant inverter stage and eliminates a switch and its controller. Electronic ballasts operating at RF frequencies require fast switching isolation diodes. Ultra-fast silicon diodes with very short recovery times, which have been used as such isolation diodes, are sensitive to ambient temperature and deteriorate the power factor and total line current harmonic distortion of the ballast. Use of either GaAs or silicon carbide isolation diodes instead of silicon diodes provides the ballast with a high power factor and a low total harmonic distortion.

Abstract: An electrodeless lamp assembly includes an electrodeless, high intensity discharge lamp capsule and a coaxial electric field applicator. The coaxial electric field applicator includes an outer conductor assembly including a tubular outer conductor having a distal end disposed at or near a first end of the lamp capsule, an outer ring disposed at or near a second end of the lamp capsule, and a plurality of cage wires connected between the outer ring and the tubular outer conductor. A center conductor assembly includes a center conductor coaxially positioned with respect to the tubular outer conductor and has a distal end disposed at or near the first end of the lamp capsule. High frequency power, supplied to the tubular outer conductor and the center conductor, is coupled by the electric field applicator to the lamp capsule. The center conductor assembly may include a guard ring positioned near the first end of the lamp capsule for concentrating electric fields in the lamp capsule.

Abstract: An electrodeless discharge lamp unit includes an electrodeless discharge lamp that has a luminescent tube with an excitation coil wound round and an auxiliary tube, a high-tension applying circuit to apply pulse voltage of a peak value that is able to dielectric break the discharge space in the luminescent tube and a current injection circuit to apply voltage, that is able to maintain non-ring shaped discharge formed in the luminescent tube by applying pulse voltage by a high-tension applying circuit even when the application of pulse voltage is suspended, to the end of the auxiliary tube.

Abstract: A fluorescent illuminating apparatus includes a translucent housing having a chamber within which a fluorescent medium is supported and electrical connections configured to provide an electrical potential across the chamber. An inductive-resistive structure is fixed sufficiently proximate to the housing to induce fluorescence in the fluorescent medium when an electric current is passed through the inductive-resistive structure while an electric potential is applied across the electrical connections of the housing. Preferred inductive structures for use with the present invention include elongate tape structures having a substrate with a conductive-resistive coating. A method of inducing fluorescence comprises passing a current through an inductive structure which is adjacent a fluorescing medium in an amount sufficient to induce fluorescence in the fluorescing medium in the presence of an electrical potential imposed on the fluorescing medium.

Abstract: Electronic ballast system for fluorescent lights. A power oscillator connected to the primary winding of a power transformer for operation at a predetermined frequency in the range of 10 KHz to 5 MHz, and a ballasting network is connected to the secondary winding of the transformer and to one or more fluorescent lamps. The ballasting network is resonant at a frequency within about .+-.10 percent of the predetermined frequency, and in some embodiments, the resonant frequency of the ballasting network remains the same regardless of the number of lamps connected to it.

Abstract: A coil assembly for an electrodeless fluorescent lamp comprises a hollow ferrite core 30, and a coil 31. The core is retained on a base 32 by a coil former 34 surrounding the core. The core 30 is retained in the former 34 by a circlip 33 or projections. The coil 31 is wound on the former. Pins 36 to which the coil is soldered connect the coil to an energizing circuit.

Abstract: The spectral energy characteristic of a discharge lamp is controlled by changing the density of the fill substance. The spectral characteristic can be shifted while substantially maintaining its shape by changing the density of the fill. A sulfur or selenium containing discharge lamp which is operated at a pressure of at least about 1 atmosphere contains a low ionization potential substance in the fill. Characteristics which are improved are one or more of spatial color uniformity, extinguishing characteristics, and bulb starting reliability. Particular substances which are added to the fill are alkali metal containing substances, III B metal containing substances, and alkaline earth metal containing substances. When light is reflected back into the bulb, the light which is re-emitted is stronger in the higher wavelengths.

Abstract: Lighting system, comprising a mercury-free metal halide lamp with a light yield of at least 75 lm/W and a color rendition index of at least 75 and an electronic ballast, the electronic ballast impressing a square-wave power supply on the lamp and keeping the power constant. The filling comprises the following components:a buffer gas which also acts as starting gas to start the lamp,a voltage gradient generator, comprising at least one metal halide which vaporizes readily and which is chiefly (by more than 50%) responsible for generating a voltage gradient which corresponds approximately to that of mercury, anda light generator comprising one metal and/or one metal halide.

Abstract: This invention is to provide an inexpensive high intensity discharge lamp lighting device having a simplified circuit construction, which does not use a full-bridge mode inverter. The high intensity discharge lamp lighting device includes a rectifier for a power-frequency power supply, a booster chopper mode sine wave converter, a zero volt switching push pull inverter, and a high intensity lamp of a halide lamp. And, as a starting device for the halide lamp, the high intensity discharge lamp lighting device generates a high voltage (5 KV) using a resonance by a ballast choke for the inverter and a condenser connected in parallel to the halide lamp, thereby inducing a glow discharge. And, a PFM (pulse frequency modulation) circuit controls the lamp current of the halide lamp to keep it constant.

Abstract: An illumination unit including an electrodeless low-pressure discharge lamp (20) and a supply device (50). The lamp has a discharge vessel (30) which encloses in a gastight manner a discharge space (31) which is provided with an ionizable filling. The lamp (20) further has a coil (40) provided with a winding (42) around a sintered core (41) of polycrystalline ferrite material, which winding (42) is connected to the supply device (50). The coil (40) is capable of inducing a high-frequency magnetic field which maintains a discharge in the discharge space (31). The losses in the core (41), when measured at room temperature in a magnetic field with a frequency of 3 MHz and a magnetic flux density of 10 mT, amount to at most 150 mW/cm.sup.3. This has the advantage that the lamp (20) ignites comparatively quickly and loads the supply device (50) comparatively weakly during ignition. The supply device (50) as a result can have a comparatively long useful life.

Abstract: Use of a side resonator group comprising a plurality of side resonators, each including both an electromagnetically inductive function section made of a substantially ringed conductive material and an electrically capacitive function section made of a gap, so arranged in a circle as to make said electrically capacitive function sections opposed to the center as high frequency energy supply means, enables a high frequency discharge to take place in a smaller space than that observed in use of a conventional cavity resonator. Besides, application of said high frequency energy supply means to a high frequency electrodeless lamp device enables high frequency energy to be effectively coupled even with a relatively small size of electrodeless discharge lamp.

Abstract: A light source apparatus excites an electrodeless lamp bulb with energy of microwaves generated from a magnetron. A microwave transmission line is improved so that microwaves can be transmitted efficiently and the light source apparatus can be miniaturized. A first cylindrical member is disposed coaxially with a direction in which microwaves generated from the magnetron are transmitted, and a second cylindrical member is disposed at the center of the first cylindrical member, thereby forming a coaxial transmission line. A coaxial oscillator is formed from the position at which the microwaves are generated to a position of 1/4 of the wavelength of the microwave. Thus, a special waveguide can be removed.

Abstract: A starting system for an electrodeless metal halide discharge lamp includes a parallel tuned LC network including a fixed capacitor and a starting inductor, and also including a conductive plate for application to the starting inductor for detuning the network once the lamp has started. The detuned starting network produces insufficient voltage to maintain the starting plasma while the lamp is running. The conductive plate is removed from the starting inductor by a solenoid or other mechanical actuator during lamp starting.

Abstract: A microwave lamp having a compact structure utilizing a coupling slot which has a dielectric member extending therethrough and a tuning block adjoining the coupling slot. A non-conventional waveguide is used which has about the width of a WR-284 waveguide and about the length of a WR-340 waveguide.

Abstract: The invention is embodied in a plasma reactor for processing a semiconductor wafer, the reactor having a pair of parallel capacitive electrodes at the ceiling and base of the processing chamber, respectively, each of the capacitive electrodes capacitively coupling RF power into the chamber in accordance with a certain RF phase relationship between the pair of electrodes during processing of the semiconductor wafer for ease of plasma ignition and precise control of plasma ion energy and process reproducibility, and an inductive coil wound around a portion of the chamber and inductively coupling RF power into the chamber for independent control of plasma ion density. Preferably, in order to minimize the number of RF sources while providing independent power control, the invention includes power splitting to separately provide power from a common source or sources to the pair of electrodes and to the coil.

Abstract: An electrodeless discharge lamp has an arc tube which seals at least rare gas and one of luminous metal and metal halide thereinto, an opening of the arc tube being vacuum-sealed with at least molten glass, and an sealing unit of the arc tube being placed outside a cavity which supplies excitation energy to make said electrodeless discharge lamp emit a light.

Abstract: The spectral energy characteristic of a discharge lamp is controlled by changing the density of the fill substance. The spectral characteristic can be shifted while substantially maintaining its shape by changing the density of the fill. A sulfur or selenium containing discharge lamp which is operated at a pressure of at least about 1 atmosphere contains a low ionization potential substance in the fill. Characteristics which are improved are one or more of spatial color uniformity, extinguishing characteristics, and bulb starting reliability. Particular substances which are added to the fill are alkali metal containing substances, III B metal containing substances, and alkaline earth metal containing substances. When light is reflected back into the bulb, the light which is re-emitted is stronger in the higher wavelengths.

Abstract: An Electrodeless High Intensity Discharge (EHID) lamp for projection applications. The lamp has a small (nominal dimensions: 2 mm I.D., 3 mm O.D., 6 mm internal length) capsule, which is constricted in a mid-portion thereof. The constriction squeezes the plasma within the capsule and provides a higher power density. This in turn produces a higher luminance in the center of the arc. This focal point of the projection system is constant over the life of the lamp, owing to the fact that the system is electrodeless. The arc tube or capsule is thickened in the vicinity of the constriction to permit heat transfer through the vitreous silica (commonly called quartz). The thickening carries the heat away from the now hotter mid-portion area. This thickening cools by virtue of increasing the thermal conduction through the glass.

Abstract: Electronic ballast system for fluorescent lights. A power oscillator connected to the primary winding of a power transformer for operation at a predetermined frequency in the range of 10 KHz to 5 MHz, and a ballasting network is connected to the secondary winding of the transformer and to one or more fluorescent lamps. The ballasting network is resonant at a frequency within about .+-.10 percent of the predetermined frequency, and in some embodiments, the resonant frequency of the ballasting network remains the same regardless of the number of lamps connected to it.

Abstract: A primary color lamp comprises a glass envelope with a krypton arc doped with metal halides. A cesium bromide or cesium iodide solution is included with lithium iodide (LiI) to produce red light, thallium iodide (TlI) to produce green light and indium iodide (InI) to produce blue light. The solution controls the vapor pressures of the lithium iodide (LiI), thallium iodide (TlI) and indium iodide (InI) and allows them to be balanced for light amplitude output. No mercury is used in order to eliminate a corresponding yellow light output and the filter complications that result in a system that operates on the primary colors.

Abstract: The invention relates to a sintered moulding of Li(Ni)Zn ferrite material, a transformer core and an inductor core of this material as well as several applications of these cores. In accordance with the invention, the majority of the grains of the sintered material have a monodomain structure. This leads to a substantial reduction of the loss factor and the overall losses when these mouldings are subjected to high-frequency applications and power applications. The ferrite material preferably comprises 59-65 mol % Fe.sub.2 O.sub.3, 7-11 mol % Li.sub.2 CO.sub.3, 4-8 mol % MnO and 20-28 mol % ZnO. This also provides the material with a high saturation magnetization.

Abstract: A microwave-excited discharge lamp apparatus of the present invention has a translucent blow guide 6 arranged around a microwave-excited discharge lamp 4. Thereby, even when the microwave-excited discharge lamp 4 is reduced in size, the microwave-excited discharge lamp 4 can be cooled efficiently without complicating or increasing the size of the apparatus.

Abstract: A high-pressure discharge lamp includes an arc tube. The arc tube is supplied with electric power having a frequency at which substantially only one sound standing wave occurs in the arc tube. The sound standing wave is of a given mode, and is in a radial direction with respect to the arc tube. The given mode corresponds to, for example, a first-order mode. Preferably, the arc tube satisfies a relation as follows:(n+0.2).ltoreq.2L/D.ltoreq.(n+0.8)where "n" denotes a natural number, and "L" denotes an axial length of an interior of the arc tube and "D" denotes an inside diameter of the arc tube.

Abstract: A light-transmitting discharge vessel (10) encloses a discharge space (11) in a gastight manner. The discharge space comprises mercury as well as one or several inert gases. The lamp is in addition provided with an electric coil (20) for generating a high-frequency magnetic field in the discharge space. The discharge lamp is provided with an auxiliary amalgam (40) which is provided on an elongate carrier (41) which is mechanically coupled to a tube (50) which issues into the discharge space. The auxiliary amalgam (40) covers the carrier (41) at least substantially entirely.

Abstract: An electrodeless high intensity discharge lamp includes an electrodeless lamp capsule having an enclosed volume containing a mixture of starting gas and chemical dopant material excitable by high frequency power to a state of luminous emission, an applicator for coupling high frequency power to the lamp capsule, a gas nozzle directed toward the lamp capsule and a gas controller coupled to the gas nozzle. The gas controller receives gas from a gas source and supplies a gas puff of limited duration to the lamp capsule through the gas nozzle in response to termination of the state of luminous emission. The lamp capsule is rapidly cooled by the gas puff to a temperature required for restart.

Abstract: An RF source is periodically pulsed for exciting an electrodeless light bulb in an on-off mode so as to intermittently drive the bulb to a high peak power operating point where light generation efficiency is relatively high, while maintaining a relatively low average power input. Pulse rate and duration are optimized to minimize light flicker while maximizing light emission efficiency.

Abstract: A discharge lamp (10) based on microwave excitable sulfur gas with enhanced red component of visible light emission from the lamp as a whole, the lamp having an arc discharge tube (18) light source, microwave excitation means (M) and an outer inert zone around the arc discharge tube having a layer of phosphor (16) selected to absorb a portion of blue-green spectral component of the arc discharge tube emission and emit a concentrated red region of spectral range of light to combine with non-red spectral components of light passing through the phosphor. The phosphor can be essentially homogeneous material or may comprise a mixture of distinct phosphor types and/or a multi-layered array.

Abstract: The envelope of an electrodeless lamp which would tend to produce a discharge which does not substantially fill the interior of the envelope if the envelope is not rotated or is rotated at insufficient speed, is rotated at a high enough speed to cause the discharge to substantially fill the interior of the envelope.

Abstract: An RF powered electrodeless lamp utilizing an inductive tuner in the waveguide which couples the RF power to the lamp cavity, for reducing reflected RF power and causing the lamp to operate efficiently.

Abstract: The invention relates to an operating circuit for an electrodeless low-prure gas discharge lamp designed for power between some watts and some kilowatts having a switching system which operates at high frequency in a freewheeling mode close to resonance.

Abstract: A discharge vessel for an electrodeless lamp having a pair of substantially parallel front and back walls. In one implementation, the front wall of the discharge vessel has a collimating structure, e.g a fresnel lens, for directing the light in a preferential direction such as in a flood light. In another implementation, the flat discharge vessel is quadrilateral and together with one or more quadrilateral excitation coils can be used as a backlight for a flat panel display. In yet another implementation, a cup-shaped discharge vessel with a collimating structure on the front wall is used in an electrodeless lamp for a task lighting such as a spot light.

Abstract: A transformerless power oscillator for driving a high intensity electrodeless light bulb. The driver uses a silicon carbide static induction transistor (SIT) operating as a power oscillator powered by an unregulated power supply potential generated by a full wave rectifier bridge connected to an AC power line. A CW output signal is generated at S-band and is coupled to the excitation coil of an electrodeless lamp by means of a matching network.

Abstract: A compact electrodeless fluorescent lamp has an A-line configuration including a globular upper portion which becomes narrower toward a lower portion, terminating in a narrow end. The narrow end of the A-line envelope is connected to a base. The alternating current energy source is electrically connected through the base, via a ballast, to the excitation coil. The ballast is integral with the lamp and is contained substantially within the re-entrant cavity.

Abstract: An electrodeless high intensity discharge lamp includes a light-transmissive arc tube for containing a plasma arc discharge, the arc tube having a top and a bottom and a side wall with a fill disposed therein. The fill includes at least one metal halide and a buffer gas. The arc tube has a wall with an interior surface having an annular region around the central extent of the side wall. The interior surface of the arc tube wall is smooth over the majority of its extent but has a liquid-stabilizing roughened surface in the annular region.

Abstract: A power source device includes a high frequency power source having a pair of switching elements and converting a DC voltage into an AC high frequency voltage to be supplied to a load, a driving transformer having, wound on a magnetic core, a primary winding and a pair of secondary windings connected respectively in series to each of control terminals of the pair of the switching elements, and a driving device for driving the two switching elements by applying a voltage to the primary winding of the driving transformer. The secondary windings are wound on the core to be separated in every turn at equal intervals and not to be intimately close to each other, for remarkable improvement in the degree of variability in the efficiency of circuit forming the power source device.