Abstract: A method for detecting the resonance frequency of an electrical oscillation circuit, in particular that of a starter oscillation circuit for high-pressure gas discharge lamps, is described in which the oscillation circuit is excited with various frequencies. The frequency search is undertaken in a search run with individual search attempts. A specific, fixed frequency is used for the sampling tests. Each fixed frequency is selected and used according to a specific search pattern. In the search pattern, the first sampling test is carried out with the mean frequency, which is the mean between the minimum and maximum possible resonance frequencies. In each of the subsequent sampling tests, the test frequency is modified in steps. The resonance frequency found in a search run can be stored as a learning frequency for use as a starting frequency for subsequent search runs and updated as necessary.

Abstract: An arrangement for detecting the condition of a high pressure gas discharge lamp when switched on is described, where a control unit either injects a defined current into the lamp and measures the resulting voltage drop, or it applies a defined voltage to the lamp and measures the lamp current flowing in so doing and, depending on the result, it starts the lamp according to the condition of the lamp thus determined.