Abstract: A method for starting a discharge lamp having two filaments includes the following steps: (1) preheating only one of the two filaments; (2) igniting the lamp; (3) operating the lamp with a direct current; and (4) powering the lamp with an alternating current. The step of operating the lamp with a direct current has a duration that is preferably between 0.1 seconds and 2 seconds.

Abstract: Appliance for discharge lamps, which has a load circuit with a resonance point at a resonant frequency fres. In order to start the discharge lamps, the load circuit is fed with a square-wave source voltage Uq, whose period duration Tper multiplied by the resonant frequency fres of the load circuit produces approximately a natural number n which is greater than 1. The pulse duration Tpulse at the source voltage Uq is in a range which is described by the following condition: 0.

Abstract: Appliance for discharge lamps, which has a load circuit with a resonance point at a resonant frequency fres. In order to start the discharge lamps, the load circuit is fed with a square-wave source voltage Uq, whose period duration Tper multiplied by the resonant frequency fres of the load circuit produces approximately a natural number n which is greater than 1. The pulse duration Tpulse at the source voltage Uq is in a range which is described by the following condition: 1 0.

Abstract: Only one filament is preheated in a preheating phase. The non-preheated filament is heated up as anode in a short DC phase after the ignition.

Abstract: The present invention relates to a method for providing an output signal (Ua) having a desired value of a characteristic quantity (Uarms) at the output of a switched-mode power supply unit. At least one low-voltage lamp is connected to the output of the switched-mode power supply unit. A load current (IL) corresponds to the sum of the currents (I1, I2) flowing through all the low-voltage lamps. The input side the switched-mode power supply unit is driven by an input signal (Ue1, Ue2) having at least one variable characteristic quantity (PW), and the switched-mode power supply unit is connected to an operating voltage (UB).

Abstract: A ballast for a gas discharge lamp having an inverter. A DC voltage source feeds the ballast. A bridge circuit is arranged in parallel with the DC voltage source. The bridge circuit has first and second controllable switches. The midpoint of the bridge is connected to a load circuit having the gas discharge lamp. The gas discharge lamp has first and second electrodes. A control circuit controls the pulse duty factor of the first and second switches. The pulse duty factor is not equal to 50%. The control circuit controls the pulse duty factor such that the first and second electrodes are subjected to essentially the same thermal load on average.

Abstract: The invention relates to a circuit for power-factor correction having a rectifier (14) which can be connected on the input side to an AC voltage source (10) and which is connected on the output side to at least one series circuit comprising a capacitor (CS1) and a diode (DS1), with the diode (DS1) being arranged such that the capacitor (CS1; CS2) cannot be charged through the diode (DS1; DS2) by the output signal from the rectifier (14), a first and a second electronic switch (T1, T2) connected in series as part of a half bridge or full bridge, each having a freewheeling diode (DF1; DF2) connected in parallel with the switch (T1; T2) and, with the [lacuna] formed by the junction point between the first and second switches (T1, T2) [lacuna] an output connection of the half bridge or full bridge is on the one hand connected via an inductance (L) to a point on the connection of the capacitor (CS1) and diode (DS1) of each series circuit comprising a capacitor (CS1) and a diode (DS1), and on th

Abstract: The present invention relates to a circuit for power-factor correction having a bridge rectifier (18) with a first and a second input connection (14, 16) in which case an AC voltage source (10) can be arranged between the first and the second input connection (14, 16), and having a first and a second output connection (30, 32), an actuation and load circuit (24), at least one energy storage apparatus, (20; 20a; 20b), whose first connection is connected to a connection (28) in the actuation and load circuit (24), in which case the signal which can be tapped off at this connection (28) in operation is at a considerably higher frequency than the output signal from the AC voltage source (10), and an energy storage capacitor (CS), wherein the energy storage capacitor (CS) is arranged in parallel with the output connections (30, 32) of the bridge rectifier (18), and the second connection of the at least one energy storage apparatus (20; 20a; 20b) is connected to one of the two input connections (14; 16) of the brid

Abstract: The invention concerns a circuit for operating a discharge lamp with a habridge generator (T1, T2) wherein a turn-off transistor (T3) can stop the half-bridge generator The energy source for the base current of the turn-off transistor (T3) is formed by starter capacitor (C3) which starts the half-bridge generator (T1, T2), In addition, the collector-emitter section of the turn-off transistor (T3) is directly between the base of the lower transistor (T2) of the half-bridge generator and earth.

Abstract: The invention relates to a radio interference suppression circuit for switching power supplies which are suitable for operating both discharge lamps and incandescent lamps. The radio interference suppression circuit has at least one controlled additional source (ZW, F) and one open-loop control circuit (TR1). The additional source or additional sources (ZW, F) generate targeted compensation signals, which are inverted with respect to the interference signals caused by the fast switching transistors (T1, T2). The additional source is either coupled parallel to the interference source and capacitively to the environment (ZW, F) or electrically connected into the supply leads in series with the interference source.