METHOD FOR MONITORING THE LIFETIME OF A FILAMENT LAMP AND FILAMENT LAMP ASSEMBLY

摘要

It is provided a method (10) for monitoring a lifetime of a filament lamp comprising the steps: measuring (11, 12) at a time t a lamp current I(t) and a voltage U(t), measuring (11, 13) at a time t+1 a lamp current I(t+1) and a lamp voltage U(t+1), checking (14) whether an equation (I(t+1)/I(t)) = k (U(t+1)/U(t))x ± e is met, wherein k and X are constants and e an allowable error tolerance, and indicating (28) an end of the lifetime of the lamp, if the equation is not met. Not monitoring a predetermined threshold of U or I but monitoring the meeting of a predetermined nonlinear relation of U to I leads to an increased accuracy for detecting the end of the lifetime of the filament lamp.