I was intrigued by the term so I looked for instances of it in archive.org . Most of the 13 matches assumed you knew what it meant. A few clarified in passing,

I was intrigued by the term so I looked for instances of it in archive.org . Most of the 13 matches assumed you knew what it meant. A few clarified in passing, like "Some metal halide lamps may fail in a non-passive manner, spraying hot glass from the shattered arc tube." My favorite was https://archive.org/details/sim_i-d_1996-11_43_6/page/15/mode/2up?q=passive https://archive.org/details/sim_i-d_1996-11_43_6/page/15/mod... : > Although the only measure most of us associate with light bulbs is wattage (which, contrary to popular belief, doesn’t measure light output but energy use), there are seemingly endless variables to consider when comparing light sources. Ask a lighting expert what you think is a simple question and you’re soon knee-deep in terms like “chromaticity,” “color rendering index,” “lumen maintenance,” “optical efficiency” and “non-passive failure” (an extremely polite way of referring to a bulb that explodes).