Abstract: A starter for igniting a gas and/or vapor discharge tube (1) comprising two main electrodes 53, 54 and an auxiliary electrode 70. The discharge tube is connected to an inductive stabilization ballast 52. The starter applies an ignition voltage between the auxiliary electrode and a main electrode of the discharge tube. Tube ignition is promoted by connecting a capacitor 55 in series with a semiconductor switching element 58 across the starter input terminals A,B so that - in addition to the said ignition voltage - an increased voltage is generated between the two main electrodes of the discharge tube by cooperation of the inductive ballast and the capacitor.

Abstract: The invention relates to a lamp unit provided with a mercury vapor discharge tube and a stabilization ballast which forms one mechanical whole therewith. This lamp unit is provided with a lamp base of a type which is customary for incandescent lamps.In accordance with the invention the discharge tube is a low-pressure discharge tube having a relatively high arc voltage. This results in a lamp unit whose ballast portion is small.

Abstract: The invention relates to an electric arrangement comprising two series-arranged discharge tubes which are provided with preheatable electrodes and which are stabilized by means of a relatively small ballast. The tubes are shunted by a semi-conductor switching element which operates in the operating condition of the tubes.According to the invention a control circuit of the semi-conductor switching element includes a non-linear circuit element which ensures that the discharge tubes do not ignite before the electrodes are in the warm state.

Abstract: An inductive stabilization ballast for a low-pressure mercury vapor discharge lamp having preheatable electrodes. The ballast includes a protective device which comprises a positive temperature coefficient resistor. The inductive portion of the ballast and the PTC resistor are disposed in the ballast so as to be insulated relative to one another, both electrically and thermally. The PTC resistor is connected in series with a glow starter in the preheating circuit of the lamp electrodes. Thus, the electric current in the case of a non-starting lamp is kept at a harmless low level and, in the case of a normally operating lamp the PTC resistor does not disturb the lamp operation.