Abstract: Switching and switchover devices for DC networks make it possible to realize, particularly in the event of faults, rapid and reliable switching processes in combination with good overvoltage damping and low energy losses during normal operation. The switching devices furthermore have short turn-off times and require no cooling since they have no on-state power losses during normal operation.

Abstract: There are provided a first coil device (102) that releases accumulated energy so as to generate a predetermined high voltage and supplies the predetermined high voltage to a first electrode (101a) of an ignition plug (101) so that a spark discharge path is formed in a gap between the first electrode (101a) and a second electrode (101b), and a second coil device (103, 301) that supplies a current to the spark discharge path formed in the gap by releasing accumulated energy; a large AC discharge current is supplied in a short cycle to the gap between the electrodes of the ignition plug (101).

Abstract: A high-pressure discharge lamp having an ignition aid, may include a discharge vessel which is fitted in an outer bulb, wherein a UV enhancer is fitted as an ignition aid in the outer bulb, wherein the UV enhancer comprises a UV-transparent can-like container having an inner wall and end side and longitudinal axis, the container enclosing with its inner wall a cavity which is filled with a gas that can emit UV radiation, an inner vent electrode, which has at least one bend or kink, being fitted in the cavity in such a way that a bend or kink lie as close as possible to the inner wall of the container, and wherein an external electrode is applied externally in the vicinity of the container.

Abstract: A long life high pressure arc discharge lamp configuration is disclosed. In some embodiments, the lamp includes a first non-cycling high pressure arc tube having a first ignition aid and a second arc tube electrically connected in parallel to the first arc tube. A lamp envelope is provided about the first and second arc tubes. In some cases, each of the first and second arc tubes is a non-cycling high pressure sodium arc tube, and each is configured with an ignition aid strip running lengthwise down the corresponding arc tube. In some cases, the first and second arc tubes are oriented such that their respective ignition aid strips are effectively 180 degrees+/?90 degrees away from each other, or so that their respective ignition aid strips are effectively 180 degrees+/?5 degrees away from each other. In some such, the second arc tube is a low-pressure arc tube.

Abstract: High pressure discharge lamp (20) with improved ignitability. A spiral pulse generator (1) that is directly mounted inside the outer piston (12) of the lamp is used for igniting the high pressure discharge lamp.

Abstract: An arc discharge lamp (60) contains an arc tube (62) containing an arc generating and sustaining medium. The arc tube (62) has at least one press seal (64). Means (66) for coupling electrical energy to the interior of the arc tube includes an electrical current-carrying frame member (68) and in-leads (68a) and (68b) sealed into the lamp stem (90) and connected to a base (not shown). A starting source (70) comprises a sealed cavity (72) formed in the press seal (64). A second fill material is contained within the sealed cavity (72). The starting source (70) emits ultraviolet radiation when the lamp (60) is energized, which assists in initiation of the arc discharge within the interior of the arc tube (62). An electrical energy coupler (74) is provided for coupling electrical energy to the sealed cavity (72).

Abstract: A high-pressure discharge lamp has a discharge vessel that is enclosed, with an interspace, by an outer bulb. The end of the outer bulb is provided with a lamp cap. The lamp has an ignition circuit including a series connection of a glow starter and an ohmic impedance. The ohmic impedance is formed by a halogen incandescent lamp. The mutual orientation of the glow starter and the ohmic impedance is such that heat produced by the ohmic impedance is at least partly intercepted by the glow starter.

Abstract: The discharge lamp of the invention includes a main discharge vessel which is filled with a discharge medium for the main discharge via a pair of opposed main discharge electrodes, and has a first electrode sealing part and a second electrode sealing part for connecting the pair of main discharge electrodes. The advantage of the invention is in a starting electrode arranged such that it does not come into contact with the main discharge space, and an auxiliary light source which includes an auxiliary discharge vessel located adjacent on the side of one of the electrode sealing parts and which is not made integral with the electrode sealing parts. The auxiliary light source is filled with a discharge medium, and has a first outer electrode on the outside of the auxiliary discharge vessel.

Abstract: A dielectric barrier discharge lamp with a discharge vessel (1) has at least one inner electrode (5a; 5b) which is covered with a dielectric layer (6a; 6b) and is arranged on the inner side of the discharge vessel (1). The at least one inner electrode (5a; 5b) is electrically conductively connected to a supply conductor (8a; 8b) in a leadthrough region, the leadthrough region being realized by a gastight pinch (9).

Abstract: A discharge units comprises a transparent envelope filled with a discharge gas containing mercury, and electrodes for exciting the gases by applying an electric field. It has been found that if, apart from the mercury vapour, the gas is about 99% argon and of the order of 0.1-1% krypton then the proportion of near-visible UV lines is increased, in relation to the 254-nm line, particularly if pulsed excitation is used. This increases the efficiency of the lamp when used to excite visible phosphors.

Abstract: A metal halide lamp includes a ceramic arc tube that is composed of a main body and two narrow tube parts provided at respective ends of the main body; a pair of electrodes provided inside the main body; two feeders, each being connected at one end thereof to a different one of the electrodes inside the main body, and extending through a different one of the narrow tube parts, so as to be external to the arc tube at another end; a starting wire that is connected to one of the feeders, and that is in a vicinity of or contacts an outer surface of the arc tube; and a current suppressing unit that is on a current path of the starting wire, and suppresses or cuts off current on the path.

Abstract: A lamp (10) includes an optics module (12) and an electronics module (14, 60, 70). The optics module (10) includes a plurality of LEDs (76) arranged on a printed circuit board (18) and having a plurality of input leads, and a heat sink (22) having a conduit (40) for the input leads. The plurality of LEDs (16) thermally communicate with the heat sink (22). The electronics module (14, 60, 70) is adapted to power the plurality of LEDs (16) through the input leads. The electronics module (14, 60, 70) has a first end (52) adapted to rigidly connect with the heat sink (22), and a selected electrical connector (50, 62, 72) arranged on a second end for receiving electrical power. The electronics module (14, 60, 70) further houses circuitry (80) arranged therewithin for adapting the received electrical power (82) to drive the LEDs (16).

Abstract: A bent fluorescent lamp for backlighting a display providing uniform illumination. A fluorescent lamp is made from a tubular glass envelope having right angles formed therein. The right angles provide improved illumination of a plane surface for backlighting a liquid crystal display. The right angles eliminate dark regions in the illuminated surface. A right-angled bend is also formed at the ends of the fluorescent lamp. An electrode is positioned sufficiently far from a central portion of the lamp so that any dark spaces in the gas discharge of the fluorescent lamp, such as the Faraday dark space associated with a cathode of a lamp are not formed within the central portion. As a result, the central portion of the fluorescent lamp has a uniform brightness or intensity providing improved illumination for backlighting a liquid crystal display. The resulting more uniform illumination with less dark regions results in a more legible display and more accurate information being displayed.

Abstract: The present invention comprises a lamp assembly with an integral circuit to provide electrical connectivity to the lamp and methods of making the lamp assembly. The integral circuit in one embodiment is constructed from a conductive polymer. The polymer may be injection molded, and the lamp assembly housing and integral circuit may be manufactured using a two-shot injection molding process. The present invention may be used in the production of a wide range of lamp assemblies, including vehicle headlamp assemblies.

Abstract: A flash lamp (10), comprising a gas-filled discharge tube (10) made of glass and, at each end, a power electrode (14, 15) that is sealed by means of a glass solder (13), has a glass including one or more of the following U.V. transmission values Tw: at 180 nm: Tw>5%, preferably >9%; at 200 nm: Tw>30%, preferably >45%; at 254 nm: Tw>60%, preferably >80%. The inside diameter of the discharge tube (11) may be larger than 1.2 times the value of the plasma channel diameter. The starting electrode (16) may be part of the reflector (30-33) or be connected electrically thereto. Flash capacitor (42) may be designed for a charging voltage above 370 volts, preferably above 400 volts.

Abstract: A ballast for electrical lighting fixtures with improved thermal protection features is disclosed. The ballast has ballast laminations, primary and secondary coils, and a thermal protector, the thermal protector being wired in series with the secondary coil. The ballast preferably is of the type having multiple input voltage taps on the primary coil; in such cases, the electrical positioning of the thermal protector in series with the secondary coil causes the wiring assembly of the thermal protector (as part of the ballast) to be independent of the primary coil input voltage tap used in a particular application. Also disclosed are improved electrical lighting circuits for high-intensity-discharge lamps, the circuits having the above-described thermally-protected ballasts.

Abstract: The invention relates to a high-pressure discharge lamp comprising a discharge vessel which is enclosed, with clearance, by an outer bulb. The outer bulb is closed at one end by a lamp cap. The lamp is provided with an ignition circuit including at least a series arrangement of a glow starter and an ohmic impedance. According to the invention, the ohmic impedance is formed by a halogen incandescent lamp.

Abstract: An arc discharge lamp system comprises a third electrode for igniting the arc discharge lamp in addition to first and second electrodes which provide a main discharge current path for sustaining arc discharge after the lamp has been ignited by a high-voltage, high-frequency signal applied to the third electrode. In an embodiment, an igniter circuit is connected to provide the high-voltage, high-frequency signal to the third electrode of the lamp by using a low-voltage DC power supply.

Abstract: A high intensity discharge (HID) lamp includes a starting gas, a vaporizable fill, and only one electrode sealed within a light transmissive envelope. The one electrode produces a high intensity discharge during operation of the lamp and is connected to an inlead that extends outside the sealed envelope. A ground for electric field lines emanating from the electrode during operation of the lamp is outside the envelope. The ground may be a reflector for the lamp that has an electrically conductive surface. The high intensity discharge is initiated by applying high frequency power to the inlead.

Abstract: Start-up and re-ignition of a high pressure arc lamp are aided by injection of electrons toward a high pressure arc lamp electrode. A microdischarge device directs electrons toward an electrode of the arc lamp and is preferably turned off during normal operation of the arc lamp. The harsh environment of an arc lamp requires the microdischarge to be made from robust materials, such as ceramics, semiconductors or tungsten, for example. In the present invention, the discharge design must allow, preferably through a screen anode, for the escape of electrons from the microdischarge. This invention results in a decrease in the voltage required to start-up or re-ignite a lamp.

Abstract: The present invention relates to a compact 3-way fluorescent lamp that is designed to serve as a replacement for a 3-way incandescent bulb. This novel compact 3-way fluorescent lamp uses only two fluorescent tubes, where one tube has twice the wattage rating of the smaller rated tube. The lower wattage unit is a single U-shaped tube and the higher wattage unit is comprised of a pair of U-shaped tubes, having a cross connection at the base of the tubes, giving a continuous gas discharge path through a first U-shaped tube, a cross connecting element, and a second U-shaped tube. Therefore, this lamp gives the appearance of a triple biaxial fluorescent lamp having three U-shaped units, spaced 120 degrees apart, and mounted to the top surface of a ballast housing cover.

Abstract: A short-arc discharge lamp (1) is provided with a light-transmitting, gastight lamp vessel (10), which is provided with an ionizable filling. A first electrode and a second electrode (11a, 11b), respectively, are arranged in the lamp vessel (10) and are each connected to a current conductor of their own (12a, 12b), respectively, which issues from the lamp vessel to the exterior. An ignition antenna (2) is arranged near the lamp vessel, which ignition antenna is connected to a further current conductor (24). The ignition antenna comprises an antenna vessel (20) and a further outer electrode (22), which antenna vessel (20) is closed in a gastight manner and provided with an ionizable filling, the further outer electrode (22) being connected to the further current conductor (24). The antenna encloses an electroconductive element. In this way, very small ignition delays are guaranteed, even if the lamp has been in a dark environment for some time.

Abstract: The invention relates to a metal halide lamp having an outer bulb containing besides a discharge vessel a UV enhancer (UVE). The UVE has a ceramic wall and, according to the invention, is provided with a pair of internal electrodes. Preferably, at least one of the electrodes has an electrode winding with emitter.

Abstract: A short-arc discharge lamp (1) is provided with a translucent lamp vessel (10) which is closed in a gas-tight manner and which is provided with an ionizable fill. A first and a second electrode (11a, 11b) are arranged in the lamp vessel (10) which are each connected to its own current conductor (12a, 12b) which extends to outside the lamp vessel. A starting antenna (2) is arranged near to the lamp vessel, which antenna is connected to a further current conductor (24). The starting antenna comprises an antenna container (20) and a further electrode (22) which antenna container (20) is closed in a gas-tight manner and contains an ionizable fill, the further electrode (22) being connected to the further current conductor (24). This makes it possible to realize a shorter reignition time by means of a higher reignition voltage on the starting antenna while spark-over from the starting antenna (2) to the lamp vessel (10) is avoided.

Abstract: A DC power source is connected to a base of a transistor of each of inverter circuits through a resistance in series. A primary winding having an intermediate tap of an inverter transformer, a resonance capacitor and a primary winding of a synchronization transformer are connected together in parallel between collectors of a pair of transistors having grounded emitters. Secondary windings of the synchronization transformers of the inverter circuits are connected together in parallel.

Abstract: To achieve the foregoing objects and in accordance with the purpose of the invention, as embodied and broadly described herein, the metal halide lamp of this invention comprises a vitreous arc tube containing an ionizable medium and having electrodes sealed into opposed ends of the arc tube. An outer envelope encloses the arc tube and includes one end accommodating inleads sealed therethrough. A base is attached to the outer envelope having input terminals, the input terminals being connected to the inleads which in turn are connected to the tungsten electrodes. A mount is provided to support the arc tube within the outer envelope. The ionizable medium will include mercury, a metal halide, and an inert gas selected from the group consisting of argon, krypton, and xenon and mixtures thereof. In addition, a starting circuit having an open circuit voltage of at least 200 volts RMS will be provided. The inert gas having a pressure of at least about 70 torr.

Abstract: A high-voltage discharge lamp has a bulb made of quartz glass, a pair of electrodes and molybdenum foils, wherein the pair of electrodes are arranged so as to oppose each other and are joined to respective ones of the molybdenum foils, and the bulb and molybdenum foils are hermetically sealed at seal portions of the bulb. The joints between the pair of electrodes and the respective molybdenum foils are covered by cylindrical members having slits on an outer surface and/or an inner surface thereof.

Abstract: Proposed is a gaseous-discharge lamp, in particular for motor-vehicle headlamps, comprising a burner vessel of glass or the like having at least two electrodes, the burner vessel being provided with a lamp base that includes the electrical terminals and that is insertable into a lamp base socket. Arranged in the lamp base is an electronic ballast unit that supplies the lamp with the necessary ignition and maintaining voltage. By accomodating the balast unit in the lamp base, one can achieve a small-volume gaseous-discharge lamp having short high-voltage leads i an integrated type of construction, making it possible to keep the ignition voltage to a minimum.

Abstract: A metal halide lamp, having a cold fill pressure of at least 50 torr, incorporates a starter circuit with an active device to protect the diode included therein. The active portion of the starter circuit, either removes a voltage multiplying circuit portion, from the starter circuit or shorts out the diode by shunting action of the switch. The voltage multiplier circuit portion is connected across the main electrodes, wherein the voltage multiplier circuit portion increases the starting voltage applied to the starter electrode.

Abstract: A planar fluorescent lamp having a resistive trace and optically transmissive cover electrodes is described. In one embodiment, the lamp includes an insulative lamp body with the transparent cover electrodes supported by the lamp cover. The resistive trace is supported by the base, either as an exterior resistive trace or within the lamp. The resistive trace acts as a heating element by producing heat in response to an electric current passed through the resistive trace. Because the resistive trace is in thermal contact with the lamp body, heat produced by the resistive trace heats the lamp, improving cold starting. The cover electrodes and, in some embodiments, the resistive trace, are used to control electric fields within the lamp body by applying voltage potentials between discrete cover electrodes or between the cover electrodes and the resistive trace. The controllable electric fields improve cold starting and uniformity of light during low light operation.

Abstract: A high-pressure discharge lamp provided with an outer bulb enclosing a discharge tube accommodates a transformer having primary winding which forms part of a current conductor to one of the main electrodes of the discharge tube. The secondary winding is coupled to an ignition electrode of the discharge tube. Higher ignition voltages can be achieved without increasing the voltage pulse on the outside contacts of the lamp.

Abstract: A fluorescent discharge lamp has two glow mode electrodes wound around it in a helical fashion. One circuit drives the main electrodes at opposite ends of the lamp at high levels of brightness. Another circuit drives the glow mode electrodes at low levels of brightness, at about 10MHz. At intermediate levels of brightness, both the main electrodes and the glow mode electrodes are driven, the two sets of electrodes being driven for alternate on and off periods with the glow mode electrodes being on when the main electrodes are off and the glow mode electrodes being off when the main electrodes are on.

Abstract: A high pressure discharge lamp having a thick film resistor comprising a plurality of resistive elements. A first resistive element is included in a starting circuit for the lamp and a second resistive element is in series with the arc tube during lamp operation for flicker elimination. The integral thick film resistor facilitates mounting and connection of the resistor elements within the lamp envelope. Favorably, the resistor substrate has a surface emissivity of greater than about 0.5, and preferably greater than about 0.9, to provide sufficient radiation cooling within an evacuated outer lamp envelope to prevent resistor failure while keeping the size of the resistor small enough for use as a component in an HID lamp. Additionally, a suitable coating of low vapor pressure thickness covers the solder connecting the metallic resistor terminals to the substrate to prevent evaporation of the solder and its deposition on the inner surface of the outer lamp envelope.

Abstract: An ultraviolet radiation starting source for an arc discharge lamp includes a sealed envelope with a press seal, a gaseous fill material within the envelope, a molybdenum ribbon which extends from the press seal into the interior region of the envelope and a wire inlead for carrying electrical energy to the ribbon. A method of manufacture is described in which fill material flows through a tube. A press seal is formed at one end of the tube, the interior of the tube is pumped to a desired pressure and another press seal is formed at the second end of the tube to create a sealed envelope.

Abstract: The invention provides a high-pressure discharge lamp incorporating an outer envelope storing a pair of electric terminals a plurality of arc tubes which are respectively stored in this outer envelope and electrically connected in parallel, and a plurality of ignition aids available for assisting operating of these arc tubes, where these ignition aids are provided for each of these arc tubes and contain potentials different from each other. In addition, the invention also provides a lighting system for operating the high-pressure discharge lamp.

Abstract: A cold-cathode fluorescent discharge tube has a pair of electrodes for performing discharge between the electrodes in response to the application of a voltage therebetween. The fluorescent discharge tube of the invention includes an auxiliary electrode provided in the vicinity of one of the pair of electrodes, and a unit for applying the voltage between the pair of electrodes and between the auxiliary electrode and the one of the electrodes. With the auxiliary electrode, a discharge is firstly started between the auxiliary electrode and the one of the electrodes in response to the application of the voltage between the pair of electrodes. Thereafter, a discharge is started between the pair of electrodes. Thus, the start discharge is generated in the discharge tube in a relatively short period of time even if the discharge tube is set in the off state for a long time, particularly in the dark at a low temperature.

Abstract: An arc discharge lamp having an arc tube mounted within a lamp envelope includes a thermal switch for controlling application of electrical energy to a starting electrode. The thermal switch is mounted between the arc tube and the lamp base with its longitudinal axis generally parallel to the central axis of the lamp envelope. The thermal switch is spaced from the central axis of the lamp envelope by a support rod and extends into an annular space between the lamp stem and the wall of the lamp envelope. As a result, the maximum temperature of the thermal switch during lamp operation does not exceed about 400.degree. C.

Abstract: A high pressure discharge lamp having a thick film resistor comprising a plurality of resistive elements. A first resistive element is included in a starting circuit for the lamp and a second resistive element is in series with the arc tube during lamp operation for flicker elimination. The integral thick film resistor facilitates mounting and connection of the resistor elements within the lamp envelope.

Abstract: A high pressure lamp assembly having an improved structure for supporting the discharge tube while providing an opening bi-metallic switch for electrically disconnecting the auxiliary electrode. Metallic frames are disposed at the upper and lower ends of the discharge lamp to provide at least partial support to the discharge tube. A non-conductive bridge assembly is connected between the lead through of the auxiliary electrode and a conductive rod extending from the stem. The non-conductive bridge provides at least partial mechanical support to the discharge tube. Connected across the non-conductive bridge is the starting resistor and bi-metallic switch element. When the bi-metallic element is unheated, it provides electrical connection through the starting resistor to the auxiliary electrode. When heated by the heat from the discharge tube, the bi-metallic switch moves out of engagement with the ceramic bridge and thus breaks the electrical connection to the auxiliary electrode.

Abstract: A metal vapor discharge lamp comprising a FEC. a semiconductor switch and a thermal response switch and operated at a supply voltage of 100 to 130 V. The thickness if the FEC is 0.45 to 0.8 mm and the breakover voltage of the semiconductor switch is 60 to 100 V so that the discharge is safely caused in a light emitting tube and lighting at a voltage of -10% of the rated voltage is enabled. The open time of the thermal response switch is not less than 30 seconds so that starting is ensured even when the dimension of the light emitting tube is long or the pressure of xenon is high.

Abstract: An electric discharge lamp is disclosed utilizing an improved thermally responsive switch for operation of an auxiliary starting electrode. The improved switch has a more compact structural configuration which further accommodates temperature excursions beyond the design closure temperature without exceeding elastic limits of the metals employed in the switch construction. A metal halide lamp of relatively compact construction which employs the improved switch is also disclosed.

Abstract: A metal halide high intensity discharge lamp having an arc tube assembly including a pair of discharge electrodes and a pair of starting electrodes. Each starting electrode is adjacent a respective discharge electrode. During starting, the lamp makes the glow discharge to arc discharge transition in a substantially shorter time than a lamp with a single starting electrode, and exhibits a substantially improved lumen maintenance.

Abstract: A high intensity discharge lamp (e.g., a metal halide) containing an arc tube having first and second electrodes respectively sealed at opposite ends thereof. An outer envelope surrounds the arc tube and has a lamp base disposed at one end thereof. The lamp base has first and second terminals for electrical connection to the arc tube. The lamp further includes means for electrically coupling each of the base terminals to a respective electrode of the arc tube. A starting circuit is disposed within the lamp electrically connected in parallel with the arc tube. The starting circuit comprises a non-linear dielectric element (e.g., a non-linear capacitor) and a glow capsule. The glow capsule is located within the outer envelope proximate the arc tube and adapted to produce ultraviolet radiation.

Abstract: A high-pressure sodium vapor discharge lamp having a discharge vessel in which main electrodes are arranged and an ignition system which comprises an electric conductor surrounding the discharge vessel over at least a part of its circumference, which conductor is electrically connected to a main electrode at least in the inoperative state of the lamp. The electric conductor is a clamping member clamping around the discharge vessel. A fixed, arcuate positioning of the electric conductor is thus obtained.

Abstract: A deuterium lamp starting circuit utilizing the arc-defining aperture cage of the lamp as the arc-starting electrode to enable the application of a positive, low starting voltage simultaneously with the application of the filament voltage. This positive, low starting voltage is applied to the cage which operates as a starting electrode. After the anode to cathode arc strikes and the anode voltage decreases below the cutoff level, current between the cage and the cathode is reduced and the current flows between the cathode and the anode of the tube.

Abstract: A high-pressure discharge lamp comprising a discharge vessel provided with an external auxiliary electrode connected to a starter circuit in the lamp. The starter circuit comprises a voltage division circuit between the connection terminals of the lamp and parallel to the discharge path. A switching element of the starter circuit shunts the voltage division circuit in part and is electrically connected to a control electrode of a semiconductor switch, connected in series with the discharge path and in parallel with the voltage division circuit. As a result a starter circuit and a lamp current limiting circuit are thus combined in the lamp.

Abstract: At least two discharge units (2, 3; 14, 15, 16; 21, 22, 23, 27, 28, 29) are ocated adjacent each other, each of the discharge units preferably including a unitary U-shaped tube having two longitudinal leg portions (2a, 2b; 3a, 3b) extending parallel to each other, and a cross portion (4, 5) connecting the leg portions at the base of the U. The free ends of the U are pinch-sealed and air-tight, and the two discharge units are so positioned relative to each other that the longitudinal leg portions extend parallel to each other, selectively, in a single plane, in parallel planes, or angled with respect to each other; the cross elements are located at adjacent end portions of the respective units.

Abstract: A metal halide arc discharge lamp comprises an arc tube containing a chemical fill including mercury and metal halides and having first and second electrodes respectively sealed at opposite ends thereof. An outer envelope surrounds the arc tube and has first and second terminals for electrical connection thereto. A source of ultraviolet radiation is provided within the outer envelope proximate the arc tube for producing radiation which illuminates the path between the electrodes of the arc tube to decrease the amount of time for generating a gaseous discharge therebetween. The ultraviolet light source includes an envelope of ultraviolet light transmitting material containing a fill material and having a single electrode sealed in one end thereof. The single electrode is electrically coupled to one electrode of the arc tube.

Abstract: A metal halide arc discharge lamp comprises an arc tube containing a chemical fill including mercury and metal halides and having first and second electrodes respectively sealed at opposite ends thereof. An outer envelope surrounds the arc tube and has first and second terminals for electrical connection thereto. An electrodeless source of ultraviolet radiation is provided within the outer envelope proximate the arc tube for producing radiation which illuminates the path between the electrodes of the arc tube to decrease the amount of time for generating a gaseous discharge therebetween. The ultraviolet light source includes an envelope of ultraviolet light transmitting material having opposing ends. Portions of the envelope of the ultraviolet light source are capacitively coupled across the electrodes of the arc tube such that the source produces ultraviolet radiation during lamp starting when the first and second terminals of the lamp are energized.

Abstract: A high-pressure sodium discharge lamp comprising a discharge vessel (3) provided with an external auxiliary electrode (11) and a built-in electric starting circuit including an electric circuit comprising a transformer winding (35a), a capacitor (33) and a semiconductor switching element (34). The circuit is connected in series with a resistor (32) electrically parallel to the discharge vessel (3) and with the transformer (35) electrically connected to the external auxiliary electrode (11). The semiconductor switching element (34) is an uncontrolled voltage-dependent breakdown element of the thyristor type having a breakdown current smaller than 1 mA at a breakdown time shorter than 10 .mu.s. The resultant lamp starts very reliably and its build-in starter dissipates only a very low power.