Abstract: In a lighting arrangement comprising a low-pressure discharge lamp and a high-frequency ballast for cold-igniting and operating the low-pressure discharge lamp, said low-pressure discharge lamp is equipped with electrodes which each comprise two or more double-spiral tungsten electrode bodies covered with an emitter. The switching performance of the low-pressure discharge lamp is very high.

Abstract: A device for operating a low-pressure sodium vapor discharge lamp without a ballast. The electrode voltage drop near a main electrode of the sodium lamp is influenced by a change in the pre-heating current of that electrode and/or a change in the effective area of the electrode. The changed electrode voltage drop thus obtained provides a mechanism whereby any changes in the lamp current are opposed so as to produce ballast-free lamp operation.

Abstract: The invention relates to a gas and/or vapor discharge lamp which is provided with a discharge tube and an outer bulb which envelops this tube, whilst the heat insulation in the space between the discharge tube and the outer bulb can be changed.According to the invention the heat insulation is changed by means of a reversible hydrogen getter which is located in the space between the outer bulb and the discharge tube. In this way it is obtained that the lamp can either be operated without a stabilizing ballast or that it is less sensitive to variations in the mains supply.

Abstract: A discharge lamp has an electrically conducting transparent layer and a temperature control which responds to variations of the lamp current to control lamp temperature. A control member causes an auxiliary current to flow intermittently through the said layer. The temperature control is adjusted so that in the operational condition the lamp will always be operating in a voltage-current range having a positive nature. As a result, the lamp does not require an electric stabilizing ballast.