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The xiphmont link is pretty good. Reminded me of the nearly-useless (and growing more so every day) fact that incandescent bulbs not only make some noise, but t
by klaff 9mo ago
The xiphmont link is pretty good. Reminded me of the nearly-useless (and growing more so every day) fact that incandescent bulbs not only make some noise, but the noise increases when the bulb is near end of life. I know this from working in an anechoic chamber lit by bare bulbs hanging by cords in the chamber. We would do calibration checks at the start of the day, and sometimes a recording of a silent chamber would be louder than normal and then we'd go in and shut the door and try to figure out which bulb was the loud one.
- 4gotunameagain 9mo agoDoes the noise increase when the bulb is near end of life, or does lifespan decrease dramatically when the noise is increased ? I imagine the noise increases when one of the supports fail, and the filament starts oscillating leading to mechanical stress and failure (not that it makes a difference, just thinking out loud)
- klaff 9mo agoI've assumed or guessed that the noisy bulb had weak spots in the coiled coil filament that changed how they mechanically respond to the temperature cycling at 120 or 100 thermal cycles per second, thereby making them noisier at end of life. I don't know if I read that or am just extrapolating from how burned out bulbs look. Halogen lamps extend the life of incandescent lamps by allowing evaporated tungsten to redeposit on the filament, which says something about the general failure mechanism.