ABSTRACT
When fluorescent lamps are operated with little or no switching, the emitter is gradually lost from the hot spot. Emitter weight tells us about life; although it can be reliably measured by breaking a lamp open, it is costly and inconvenient to do it. The heat capacity of the coil depends on the emitter weight, so an electrical method of measurement can be used in principal. In a 1953 patent [1] this suggestion was explored, but measurement techniques were not up to the task; automation is needed to provide sufficient results for statistical reliability.
