內容簡介

Tungsten-filament incandescent lamps exhibit a very-high
positive temperature coefficient of resistance with the cold filament
resistance being approximately 10% of the hot filament resistance.
When an incandescent lamp is initially turned on, the cold filament
is at minimum resistance and will normally allow a 10x to 12x peak
current. Within 3 to 5 ms the current falls to approximately 2x the
hot current. This high lamp turn-on current (commonly called
“in-rush” current), can contribute to poor lamp reliability and can
destroy semiconductor lamp drivers. Even if the active part of the
driver output could survive the short-duration peak current, the
internal bonding wires can “fuse” open. High-current drivers or
paralleled drivers, rated to handle the peak inrush current, may
prove cost prohibitive.

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