One thing to consider when comparing these, is that the filament in a
lamp is lit to incandescence, higher temperature, than the filament
in a TT or oxide cathode filament. These are typically less than
2000K, dull orange or less for oxide cathode. Also, the light bulb
filament, does it use thoria in it or is it pure tungsten? Way
different mechancially. Finally, the light bulb filament, in my
recollection, is coiled like a tiny spring, or so i thought. Tube
filaments are bars, strands, sometimes coils, but much different
geometry. In some tubes they are tensioned with a mechanism to allow
for changing dimensions when they warm up.
John
K5PRO
>
>I wonder if the filament life of an ordinary incandescent light bulb relates
>to that of an RF power tube. One can fairly easily see the vibration set up
>in the light bulb filament at turn-on. I guess the vibration is caused by a
>combination of AC voltage cycles and heating of the filament.
>
>73, Keith NM5G
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|