Operating point dependent lifetime estimation of small sized tungsten incandescent lamps

摘要

The lifetime of modulated incandescent lamps depends on modulation parameters like frequency, amplitude and the type of modulation. In contrast to well-known methods of DC lifetime estimation, this paper describes the lifetime estimation of modulated small sized tungsten incandescent lamps. For that purpose the approved procedure of material evaporation was compared with a method based on electrical lamp data only. They both were specified for DC operation, so the most suitable procedure was chosen and adapted for lifetime estimation at modulated operating points. To verify this procedure, lamps were tested at different modulated points of operation. A comparison of measured and estimated lifetime shows, that the new procedure is suitable to estimate the lifetime sufficiently. This method does not require any knowledge of geometrical lamp parameters like filament's dimensions. It is based on time dependent voltage and current data which can be measured easily and it forms an adequate method for lifetime estimation of incandescent lamps, applicable for different types of modulation.