Abstract: The invention relates to an operating circuit for a discharge lamp, having a detection circuit for identifying the proximity to capacitive operation, which uses lamp current fluctuations for detection purposes.

Abstract: The invention relates to an operating circuit for a discharge lamp with a current regulation circuit for regulating the lamp current and a detection circuit for identifying proximity to capacitive operation of the load circuit. The operating circuit is designed to reduce the nominal current value on identifying proximity to capacitive operation.

Abstract: Free-running half-bridge inverter (HP) for operating gas discharge lamps having a current transformer as a feedback device. The half-bridge transistors (T1, T2) are essentially voltage controlled transistors (MOSFET). The drive circuits (1, 2) for the half-bridge transistors (T1, T2) contain a voltage threshold value switch (D2, R2) which, on reaching its voltage threshold, essentially carries a current which is proportional to the load current of the half-bridge inverter (HB).

Abstract: The invention relates to an operating circuit for a discharge lamp, having a detection circuit for identifying the proximity to capacitive operation, which uses lamp current fluctuations for detection purposes.

Abstract: The invention relates to a novel operating circuit for a low-pressure gas discharge lamp 1 in the case of which a digital controller 12 is designed such that by gradually lowering the operating frequency in the ignition procedure it initiates shutdown operations of a safety shutdown device for excessive currents through a lamp inductor 10 in order thereafter to increase the operating frequency somewhat. It is possible overall in this way to achieve an ignition, for example by repeated pulsed ignition operations as far as shutdown operations, or else by a continuous ignition operation at a minimum frequency at which no shutdown operation occurs. The invention has the advantage of being insensitive to temperature fluctuations and component tolerances and, moreover, of permitting the lamp inductor 10 to have comparatively small dimensions.

Abstract: The invention relates to a ballast for a lamp having an inverter which comprises at least one switch (S1; S2), and having a drive circuit (10) for alternately opening and closing the at least one switch (S1; S2) wherein the drive circuit (10) is designed to drive the at least one switch (S1; S2) alternately at at least two different frequencies (&ohgr;a, &ohgr;b). It also relates to a method for operating a ballast for a lamp having an inverter which comprises at least one switch (S1; S2), and having a drive circuit (10) for alternately opening and closing the at least one switch (S1; S2) wherein the drive circuit drives the at least one switch (S1; S2) alternately at at least two different frequencies (&ohgr;a, &ohgr;b).

Abstract: The invention relates to an operating circuit for a low-pressure discharge lamp LP, in which the lamp electrodes can be preheated by means of a resonant circuit C14, T11. In order to determine the resonant frequency accurately and to establish the lamp type being used, a frequency range is moved through at the start of operation and the voltage is measured on a primary winding T11 of a preheating transformer.

Abstract: The invention relates to a device for generating digital control signals having the following features: an oscillator (10), which has a digital output two storage means (20, 30) for storing the value of digitally coded variables, which each have a clock input (22, 31) connected to the digital output (11) of the oscillator (10), a data input (21, 32) and a data output (23, 33) an adder (40) which has two data inputs (41, 42), a data output (43) and a carry output (44), where the first data input (41) of the adder (40) is connected to the data output (23) of the first storage means (20), the second data input (42) of the adder (40) is connected to the data output (33) of the second storage means (30), the data output (43) of the adder (40) is connected to the data input (32) of the second storage means (30), and the carry output (44) of the adder (40) is connected to a pulse divider (50).

Abstract: The invention relates to a circuit arrangement for operating at least one discharge lamp, which has a half-bridge inverter (T1, T2, A) with a downstream load circuit (LD, CR) and has a half-bridge capacitor (CK) and also a monitoring apparatus for monitoring a change in the voltage drop across the half-bridge capacitor (CK) which is caused by the occurrence of a rectifying action in the at least one discharge lamp LP. According to the invention, the monitoring apparatus has a first RC element (R1, C1) and a second RC element (R2, C2), which are connected to one another by a threshold switch (DC), and means for detecting the switching state of the threshold switch (DC). The first RC element (R1, C1) is connected to the center tap of the half-bridge inverter, and the second RC element (R2, C2) is connected to the half-bridge capacitor (CK).

Abstract: The invention relates to an coil former and at least one wire winding arranged on the coil former, the coil former (1) having a cylindrical sleeve (1a) whose cylinder axis runs parallel to the winding axis (A—A) of the at least wire winding, and at least two side walls (1b, 1c) arranged perpendicularly to the winding axis (A—A), and the cylindrical sleeve (1a) and the side walls (1b, 1c) forming at least one winding space for the at least one wire winding (2, 3). According to the invention, the at least two side walls (1b, 1c) each have at least one shoulder (1d, 1e), which subdivide the at least one winding space into a non-constricted first region (B1) and into at least one constricted second region (B2). In addition, the inductance element has electrical insulation (5), which bears on the at least one shoulder (1d, 1e) of the side walls (1b, 1c) and separates the non-constricted first region (B1) from the at least one constricted second region (B2).