AMB rašė:
> va kazka radau, bet cia jauciu kitoje vietoje negu tada buvau rades:

Tikroji nuoroda į citatas yra „The Great Internet Light Bulb Book“:
http://freespace.virgin.net/tom.baldwin/bulbguide.html

Kaip ir labai į temą skyrelis „Halogen Bulb Failure Modes“, kurio šmotą 
ir pacituosiu:

Halogen bulbs usually fail the same way that ordinary incandescent bulbs 
do, usually from melting or breakage of a thin spot in an aging filament.
Thin spots can develop in the filaments of halogen bulbs, since the 
filaments can evaporate unevenly and the halogen cycle does not 
redeposit evaporated tungsten in a perfect, even manner nor always in 
the parts of the filament that have evaporated the most.
However, there are additional failure modes.
One failure mode is filament notching or necking. Since the ends of the 
filament are somewhat cool where the filament is attached to the lead 
wires, the halogen attacks the filament at these points. The thin spots 
get hotter, which stops the erosion at these points. However, parts of 
the filament even closer to the endpoints remain cool and suffer 
continued erosion. This is not so bad during continuous operation, since 
the thin spots do not overheat. If this process continues long enough, 
the thin spots can become weak enough to break from the weight of the 
filament.
One major problem with the "necked" ends of the filament is the fact 
that they heat up more rapidly than the rest of the filament when the 
bulb is turned on. The "necks" can overheat and melt or break during the 
current surge that occurs when the bulb is turned on. Using a 
"soft-start" device prevents overheating of the "necks", improving the 
bulb's ability to survive "necking". Soft-start devices will not greatly 
extend the life of any halogen bulbs that fail due to more normal 
filament "thin spots" that run excessively hot.
Some halogen bulbs may usually burn out due to filament end necking, and 
some others may usually burn out from thin, hot spots forming in the 
filament due to uneven filament evaporation/recovery. Therefore, some 
models may have a significantly extended life from "soft-starting" and 
some other models may not.