Abstract: A lighting system having a high pressure gas discharge light source and an incandescent light source within a common sealed and evacuated bulb. A ballast unit fitted externally to the neck of the bulb includes in series with the incandescent light source an interrupter element and control circuitry therefor, and a choke coil in series with the gas discharge light source.The control circuitry represents an equivalence logic with two variables, wherein the output terminal of an equivalence circuit is connected to the control input of the interrupter element while its input terminal is connected to a voltage divider system connected across the gas discharge light source. The output terminal is energized only if either both or neither of the input terminals of the equivalence circuit are energized. The interrupter element is closed when the output terminal of the equivalence circuit is energized.

Abstract: A high frequency ballast circuit for a discharge lamp particularly of the so-called energy saving type adapted to fit into conventional incandescent lamp sockets. The circuit comprises an inductive choke and a transistor switching device connected in series with the lamp and a rectified source of AC supply. The transistor is switched with a high frequency, preferably asymmetrically square, waveform and a diode having a direction of conduction opposite to that of the transistor is connected in shunt across the series-connected choke and lamp. The circuit enables lightweight air core coils to be used for the inductive choke facilitating integral combination of the circuit and discharge lamp into a lamp unit having the same general configuration as a conventional incandescent lamp.

Abstract: There is disclosed an electric lamp with a ceramic discharge tube and a current inlead consisting of two or more elementary filaments passing through a ceramic closing member and soldered thereto. In the tube there is an auxiliary electrode. The elementary filaments are preferably niobium. At least two of the elementary filaments are short circuited at both sides of the closing member and an auxiliary electrode is interlaced with the elementary filaments outside the discharge space.

Abstract: The high-pressure electric discharge tube of the invention can operate in the open air, with at least 10 Hg mm inner pressure. It has a preferably ceramic (or crystalline) envelope that constitutes an illuminator, with electrodes disposed in two opposite portions of the envelope, appropriate inlets, lead-ins and terminals leading to the electrodes. The discharge tube does not have to be surrounded by the hitherto applied, conventional, glass or other transparent protective envelope, as a result of which the emitted luminous output is free from reflections and the tube can be used throughout the entire spectrum, such as for pumping or driving a laser crystal. The protective envelope, which so far has been an indispensable part of all high-pressure discharge tubes, has been eliminated as a result of the present invention. Adapter tubes are used that prevent oxidation of the electrical elements, as well as specially configured electrodes.

Abstract: Electric discharge tube having a hollow cylindrical bulb formed either of a ceramic material or from sapphire having first and second open ends. First and second end caps or closure members are fitted over the ends to form capillary action passages between the first and second closure members and the end portion of the bulb member such that solder will flow when heated to join the members together on cooling of the solder. One or more of the end closure members may have a metallized surface formed thereon. The end closure members may extend along either the inside or the outside surface of the cylindrical bulb member or both the inside and the outside surfaces of the bulb member. A hollow cylindrical ceramic member may be fitted to the end portion of the bulb member and itself be fitted with a plurality of closure members at one of its ends and a third hollow ceramic member at its other end to form an air-tight sealed tube.

Abstract: Manufacturing tubeless executed high pressure ceramic or monocrystalline vacuum metal vapor lamps. The substance introduced into the discharge tube is degassed by heating the tube at least once before sealing it finally. The equipment employed in carrying out the method preferably comprises two heaters to be accommodated at the ends of the discharge tube, the heat zone of which is about 1/3 of the discharge tube length. The additives are placed into the sealed end of the discharge tube, and while heated, the tube is pumped on the other end. The additives precipitate on the colder wall parts of the discharge tube, but at the same time it is also freed from its gas content. Thereafter the precipitate is evaporated by heat treatment. This double evaporation results in a high grade degassing of the substance. Afterwards the opposite end of the discharge tube is finally sealed.