Abstract: The invention concerns a circuit for operating a discharge lamp with a habridge generator (T1, T2) wherein a turn-off transistor (T3) can stop the half-bridge generator The energy source for the base current of the turn-off transistor (T3) is formed by starter capacitor (C3) which starts the half-bridge generator (T1, T2), In addition, the collector-emitter section of the turn-off transistor (T3) is directly between the base of the lower transistor (T2) of the half-bridge generator and earth.

Abstract: A circuit arrangement (4) for the operation of electrical lamps, with a printed circuit board (5), on which electrical components (14) and conductor strips (7; 19; 20) are arranged, whereby potential changes that are rapid over time occur on printed circuit board (5), has an equipotential surface (6) for reducing the radio interference caused by these potential changes. For this purpose, equipotential surface (6) with resting potential relative to the rapid potential changes is connected onto printed circuit board (5). In particular, the equipotential surface is produced by a copper layer (6) on the upper side of printed circuit board (5). The advantage is a simple-to-produce arrangement that can be automated for reducing radio interference.

Abstract: The invention relates to an electrode for discharge lamps, with an electron mitter which contains a barium compound from the group barium zirconate (BaZrO.sub.3), barium hafnate (BaHfO.sub.3), barium titanate (BaTiO.sub.3) and barium cerate (BaCeO.sub.3) as well as one or more metallic components.

Abstract: A circuit is proposed for the high-frequency operation of at least one lamp with an active harmonic filter with at least one capacitive pump branch with a pump capacitor (C1; C2) for feeding the energy back to a filter capacitor (C4) from a connection point on the lamp side between and including a central tap of the push-pull frequency generator and a first lamp diode, is characterized by the fact that a trapezoidal capacitor (CT1; CT2) is provided between a point of at least one pump branch, which, from the central tap of the push-pull frequency generator, lies out behind capacitor (C1; C2) of the pump branch, and one of the external taps, and thus the one or more pump capacitors of the one or more pump branches are the only capacitors connected in a direct capacitive load at the central tap of the push-pull frequency generator and/or no resonance capacitor (C6) connected directly in parallel to the lamp in the operating state is provided for lamp ignition.

Abstract: A circuit arrangement for operating electrical incandescent bulbs, particrly low-volt halogen incandescent bulbs, comprises an inverter in the half-bridge circuit and an overload detector circuit, which comprises a current-voltage transformer, e.g., a resistance (R4), which is serially connected between first half-bridge capacitor (C3) and ground potential. The current-voltage transformer controls a signal-conditioning and cutoff circuit (R5-R7, C4, C5, D4, T3), which disconnects the inverter at least temporarily in the case of overload or short circuit. Preferably, current-voltage transformer (R4) of the overload detector circuit is a component of a frequency adaptation circuit (L1, R4), which opposes a decrease in the frequency of the inverter in the upper power connection range. This variant is particularly cost-favorable, since in this case, no additional component is required for detector circuit (R4).

Abstract: The invention concerns an electrical incandescent lamp with a low-beam cap, articularly a two-filament halogen incandescent lamp and a production process for such a lamp, as well as a low-beam cap. Low-beam screening cap (12) has an opening (14), through which one end (6a) of low-beam filament (6) is threaded. This filament end (6a) is welded to the back side of low-beam screening cap (12) or to a current lead wire (8a), which is attached by a projection welding to the back side of low-beam screening cap (12). The fastening of low-beam filament (6) according to the invention makes possible materials savings in the case of a low-beam screening cap (12) and lower cost lamp manufacture.

Abstract: The invention concerns a high pressure discharge bulb. Such bulbs involve a wo-sided sealed bulb with and without an outer bulb. The bulb is sealed by a pinch on at least one side. It generally has a discharge vessel made of quartz. These bulbs particularly comprise metal halide bulbs, which have a metal halide filling in addition to mercury, but they also include mercury high pressure discharge bulbs or xenon high pressure discharge bulbs. The bulbs are used preferably for optical systems, particularly larly for photo-optical purposes, for example, in head-lights, overhead projectors, and decorative lighting devices. They particularly find application in lighting systems for the stage, film and television. Typical lamp powers are 400 to 2000 W. A discharge lamp pinched on each end has pinches in which the ratio of the total width of each wide side is smaller than or equal to 2.2 times the thickness of the wide side. Tube pieces carrying the base sleeves are formed on the outer ends of the pinches.

Abstract: The circuit arrangement according to the invention has a self-oscillating inverter having at least two alternately switching transistors (Q1, Q2), a load circuit connected to the inverter output and designed as a resonant circuit (L1, C1), and terminals for at least one electric lamp (LP). According to the invention, the control junction of a transistor (T1) is arranged in the emitter line of one of the inverter transistors (Q2). Via the variable conductivity of this control junction, the effective emitter resistance of the inverter transistor (Q2) is continuously varied as a function of the voltage drop across one of the resonant circuit components (C1), and the clock frequency of the inverter (Q1, Q2) is thereby increased so far that because of the now stronger detuning with respect to the resonant frequency of the resonant circuit (C1, L1) a reduction in the no-load voltage in the load circuit is achieved.

Abstract: A ceramic discharge vessel (8) for a high-pressure discharge lamp has a pin-like feedthrough (10) inserted in a plug (11) made from a composite material. The feedthrough (10) has been sintered directly into the plug (11) and is additionally sealed by covering the area, surrounding the feedthrough, of the plug's surface facing away from the discharge volume with a ceramic sealing material (7a).

Abstract: To essentially eliminate aluminum and silicon as contaminants in a doped tungsten wire, the tungsten wire is obtained by mechanical working of reduced tungsten blue oxide which contains as a primary or major constituent a special hexagonal ammonium tungsten bronze of the general formula (NH.sub.4).sub.X (NH.sub.3).sub.y WO.sub.3. A liquid doping step is carried out by adding a solution containing potassium nitrate, the special doped ammonium tungsten bronze forming preferably more than 70% by weight of the overall tungsten blue oxide. The special hexagonal ammonium tungsten bronze is made by decomposing ammonium paratungstate in an ammonium atmosphere, preferably at a temperature between about 400.degree. and 550.degree. C.

Abstract: The invention relates to a circuit arrangement for operating electric lam and an operating method for electric lamps. The circuit arrangement has an inverter ((Q1, Q2) with a switch-off device which switches off the inverter (Q1, Q2) in the case of an anomalous operating state. The switch-off device has a field-effect transistor (T1, T1') whose drain-source junction is arranged in the control circuit of an inverter switching transistor (Q2) and switches the control circuit of the inverter transistor (Q2) between a state which is of low resistance in normal operation and a state which is of high resistance in anomalous operation. After the occurrence of an anomalous operating state, it is advantageous to switch off synchronously with the blocking phase of the inverter transistor (Q2) in whose control circuit the field-effect transistor (T1, T1') is arranged.

Abstract: A low-pressure mercury-vapor discharge lamp, which is equipped with Hg or amalgam, has a pumping tube opening (4) with constricted cross-section or lumen. A solid body in the pumping tube (3) prevents the mercury from emerging into the discharge space. At the same time, the particular shape of the constriction and of the solid body, respectively, makes it possible for Hg vapor to diffuse through-passages between the pumping tube and the solid body into discharge vessel.

Abstract: To retain an electric lamp bulb (1), without cement, in a base sleeve (2), nd provide a strain relief for insulated connection leads (6, 7) extending from the lamp, the base is formed of a metallic base sleeve having two opposite side walls (2a, 2b); a base block formed of two parts (3a, 3b) is located within the base sleeve, the parts being essentially F-shaped defining recesses which, when the parts are placed against each other with the recesses facing each other, form through openings (4, 5) within which the electrical connection leads (6, 7) are located. The parts are slightly smaller than the width of the base sleeve, and, upon deformation of the side walls of the base sleeve, for example by forming inwardly projecting dimples (9), the parts are shifted against each other and the insulated electrical connection leads are thereby clamped in the through openings, providing strain relief.

Abstract: Soft quartz glass having low viscosity and a low thermal coefficient of expansion, high electrical insulation capability and free from release of contaminants, when used as a bulb of an incandescent lamp or as an envelope in an arc vessel of a discharge lamp, is a quartz glass made of ultra-pure quartz (SiO.sub.2), for example having a purity of 99.99 mol-%, doped with stoichiometric compounds of alkaline earth oxides with boron oxide, optionally also with a small quantity of Al.sub.2 O.sub.3 in an overall quantity of the doping substance of between about 0.05% to 0.8%, by weight.

Abstract: To permit easy assembly of a filament for a halogen incandescent lamp hav a filament holder frame (4) to retain an essentially planar filament (11) in position, the frame is made of two pre-manufactured identical frame halves (4a, 4b). Both frame halves have a cross element (7a, 7b), having a plurality of filament holders (10a, 10b) secured thereto, and two support strut portions (8a, 9a, 8b, 9b) at the ends thereof. To assemble the lamp, the two frame halves, together with the filament (11), are placed in a suitable jig, and the filament ends are threaded on one of the support strut portions (8a, 8b) of each one of the frame halves. The filament (11) is hooked on the filament holder (10a, 10b) and, by spreading apart the frame halves, the filament is stretched. The support strut portions (8a, 8b; 9a, 9b) are then connected by welding, thus completing the frame (4), and retaining the filament in stretched position.

Abstract: A high pressure discharge lamp having an extended life includes a discharge vessel 8, and a feedthrough 10 extending through a plug 11. A directly sintered connection is formed between the feedthrough 10 and the plug 11 wherein sealing material 7 is provided covering the area surrounding the feedthrough on the outer surface of the plug 11. The plug 11 is formed of a composite material whose thermal expansion coefficient lies between that of the ceramic vessel and of the metal feedthrough.

Abstract: To be able to accept high-voltage pulses, in the order of 70 kV, required r re-starting a hot high-power high-pressure discharge lamp, having a power rating, for example, of 6 kW and up, including 12 kW, a ceramic base is provided with auxiliary mica strips or plates (13) positioned between part of the terminal posts or pins, and especially in the region of retentions flanges or rims formed thereon, and extending up to about the end portion (4a) of a pinch or press seal, into which connection leads extend, connected to the pins or posts. The additional mica strips or plates (13), for example located on both sides of a central separating strip (10), retained in suitable grooves or slots (14) formed in the base effectively prevent arc-over, creep currents and corona discharge between the terminal pins or posts (8a, 8b), the circumferentially projecting flanges or rims (16a, 16b) and the connected current supply leads (7a, 7b).

Abstract: Soft quartz glass having low viscosity and a low thermal coefficient of expansion, high electrical insulation capability and free from release of contaminants, when used as a bulb of an incandescent lamp or as an envelope in an arc vessel of a discharge lamp, is a quartz glass made of ultra-pure quartz (SiO.sub.2), for example having a purity of 99.99 mol-%, doped with stoichiometric compounds of alkaline earth oxides with boron oxide, optionally also with a small quantity of Al.sub.2 O.sub.3 in an overall quantity of the doping substance of between about 0.05% to 0.8%, by weight.

Abstract: To reduce flicker in low-power, high-pressure discharge lamps, the electrs, in the region in which they face each other, have wrap windings, of about 2 to 4 turns wrapped thereabout and the terminal end of the electrode has an essentially spherical end head element (19, 19', 39) melted thereon, which essentially spherical head element may be a segment of a sphere, ellipsoid-shaped or similarly formed. The electrode shaft, the wrap winding and the sphere preferably are all made of undoped tungsten, although the electrode shaft may be of a lower melting metal, such as rhenium.

Abstract: To retain an electric lamp in position within the box, in which the elect lamp has a base with projecting terminal pins (21), in such a manner that the pins (21) cannot push through and extend from the box. The box is formed with dust flaps (10, 11) which are folded inwardly to form an essentially triangular, inwardly extended projection or bridge. The so folded dust flaps (10, 11) are formed at their free ends with interengaging teeth and recesses, the interengaging apex of the triangular support structure engaging against the base (20a) of the lamp and forming a corner with one of the sidewalls (3) in which the pins (21) from the lamp (20) can fit, while the lamp itself is securely retained in immovable position of the box. The angle of the dust flaps (10, 11) with respect to the adjacent sidewalls (1, 3) can suitably vary within about 45 and 70 degrees.