Abstract: A circuit arrangement for operating at least one electric lamp having an inverter has at least one first and one second bridge transistor arranged in series with one another, a first drive circuit for the first bridge transistor; a second drive circuit for the second bridge transistor; the and second drive circuits being designed to drive the first and second bridge transistors to switch alternately completely on and off during normal lamp operation; and at least one protective apparatus; the at least one protective apparatus being designed, in the case of a value for a reference voltage, which is correlated with the voltage across the bridge transistor which has just been switched off, above a predeterminable limit value, to drive the bridge transistor, which has just been completely switched on, such that it is no longer completely switched on. A related method is also described.

Abstract: A circuit arrangement for driving electrical loads such as High Flux (HF) LEDs used as lighting sources. The circuit arrangement includes: a switched power source (10) providing a voltage signal switched with a switching frequency (Fsw) and having a given amplitude (Vout), and a plurality of cells (20) connected to the switched power source (10), wherein the LED cells (20) each include an LC decoupling impedance (50) for defining the intensity of the current flowing into the LED cell (30) from the switched power source (10). The LC decoupling impedance (50) includes LC components defining a resonance frequency (Fres) such that the switching frequency (Fsw) of the switched power source (10) is about one half the resonance frequency (Fres) of the LC decoupling impedance (50), whereby the average intensity of the current flowing into the cell is kept constant irrespective of the load on the LED cell (20).

Abstract: A process for producing an electrode for high-pressure discharge lamps, at least the discharge-side section of the electrode being produced from a prefabricated tungsten wire, which is shortened to the required length during the production process of the electrode and subjected to an annealing process as well as being mounted on other components of the electrode that may be present. The annealing process is carried out exclusively at temperatures below 1500 degrees Celsius. The invention also relates to an electrode for high-pressure discharge lamps, at least the discharge-side section of the electrode being constructed as a tungsten rod that has a long crystalline structure or an isotropic crystalline structure with grain diameters in the radial direction of the tungsten rod of less than or equal to 50 micrometers with the centroid of the grain size distribution in the range from 10 micrometers to 20 micrometers.