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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.

Background Contemporary resuscitation guidelines for basic life support recommend an immediate onset of cardiac compressions in case of cardiac arrest followed by rescue breaths. Effective ventilation is often omitted due to fear of doing harm and fear of infectious diseases. In order to improve ventilation a pre-stage of an automatic respirator was developed for use by laypersons. Methods Fifty-two healthy volunteers were ventilated by means of a prototype respirator via a full-face mask in a pilot study. The pre-stage public access ventilator (PAV) consisted of a low-cost self-designed turbine, with sensors for differential pressure, flow, FO2, FCO2 and 3-axis acceleration measurement. Sensor outputs were used to control the respirator and to recognize conditions relevant for efficiency of ventilation and patients’ safety. Different respiratory manoeuvres were applied: a) pressure controlled ventilation (PCV), b) PCV with controlled leakage and c) PCV with simulated airway occlusion. Sensor signals were analysed to detect leakage and airway occlusion. Detection based upon sensor signals was compared with evaluation based on clinical observation and additional parameters such as exhaled CO2. Results Pressure controlled ventilation could be realized in all volunteers. Leakage was recognized with 93.5% sensitivity and 93.5% specificity. Simulated airway occlusion was detected with 91.8% sensitivity and 91.7% specificity. Conclusion The pre-stage PAV was able to detect potential complications relevant for patients’ safety such as leakage and airway occlusion in a proof of principle study. Prospectively, this device provides a respectable basis for the development of an automatic emergency respirator and may help to improve bystander resuscitation. Electronic supplementary material The online version of this article (10.1186/s12873-017-0150-5) contains supplementary material, which is available to authorized users.