Abstract: The assembly has a low-pressure sodium discharge lamp (1), of which the outer envelope (4) has an electrically conducting coating (5), which is connected through a capacitor (29) to one of the current supply conductors (13) to the light source (3) of the lamp (1) and to the neutral conductor (18) of the power supply (2), which supplies an alternating voltage having a frequency of at least 80 kHz. The lamp holder (23) has an eccentrically arranged projection at its inner surface while the lamp cap (6) has an eccentrically arranged recess at its outer surface, which, when the lamp cap (6) is arranged in the lamp holder (23), engage with each other and guarantee a connection of the capacitor (29) to the neutral conductor (18). The lamp (1) is suitable for operation at mains voltage frequency and is still fitting into the lamp holder of mains voltage frequency equipment.

Abstract: A low-pressure sodium vapor discharge lamp provided with a discharge tube having an electrical lead-through conductor extending through the wall of the discharge tube to an internal lamp electrode. The lead-through is enveloped by a protective glass layer having a double bead construction. The layer portion facing the electrode is borate glass and is thinner than a second portion within the discharge tube wall which is lime glass. The lead-through construction thus obtained has a high resistance to sodium in the discharge tube and also to mechanical forces.

Abstract: An arrangement including a frequency converter (4) and a discharge lamp (10) connected thereto wherein the frequency converter (4) is of a type whose output frequency is at least 80 kHz, while the lamp is a low-pressure sodium vapor discharge lamp. This lamp supply system provides a high luminous efficacy for the lamp.

Abstract: Low-pressure sodium vapor discharge lamp. The lamp comprises a cylindrical discharge tube and an outer bulb enveloping this tube. The outer bulb has a transparent layer which reflects infrared radiation.According to the invention the resistance per square of the infrared reflecting layer is approximately 5 ohm. A luminous efficacy of 100 lumen per watt can be obtained at a lamp power of 8 watts. The lamp is particularly suitable for security lighting.

Abstract: A method of making a heat-reflecting filter consisting of a tin-doped indium oxide layer on a carrier. A tin-doped indium oxide layer is provided on a carrier by spraying a heated carrier with a solution of an indium salt and a tin salt. The layer is then reduced at 350.degree.-400.degree. C. by means of a gas flow of hydrogen, nitrogen together with oxygen or air.