🚀 go-pugleaf

In article <FISH.90Nov28100429@his.gemed.com> fish@gemed.ge.com (Mark Fisher, GE Medical, Milwaukee WI, x4-6553) writes:
>I think I can answer my own question.  I went to the hardware store
>and looked at some quartz-halogen replacement bulbs.  They have what
>appears to be a tungsten filament wire inside a quartz tube.  Going
>off the deep end, I would say that the resistance of the wire would
>limit the current and no ballast is needed.

A quartz-halogen bulb is no different from a regualar incandescent in as
much as how the power should be supplied to it.  Most of the "Indoor"
type of fixtures use bulbs that run at 12V (For many reasons). This is
why in some fixtures there is a step-down transformer.  It is not being
used for current limiting or starting as it would be in a flourescent.
Many "Outdoor" Halogens tend to use the line voltage directly.

>I looked up halogen in my dictionary.  It said it was one of the very
>active chemical elements, fluorine, chlorine, bromine, astatine, or
>iodine. How does this apply to a light bulb?

When the bulb is run in the correct temperature range, the halogen
causes re-depositing of the tungsten that is boiled off the filament
at the elevated temperature.  At lower temperatures (ie. light is 
dimmed with a dimmer) the boiling of tungsten from the filament is
not a large effect so the scrubbing and re-deposition of the tungsten
is not so important.

Lastly, I am suspicious in general of many of the "indoor" halogen
types of lights.  To get maximum "light for the buck" a halogen bulb
must be run a LOT hotter than the ones I see in stores are. Specifically
I have done quite a bit of theater lighting using lots of halogen
equipment, and usually when a light is on full, in order to get
proper re-deposition the quartz tube will glow bright red.  It will
also keep glowing for several SECONDS after the light is shut down.
This is the temperature they must be run at to make the halogen inside
be reasonably useful.  Otherwise you may as well have regular light
bulbs.

As far as getting oil on the bulbs (from skin or other things), if
the bulb is run in the correct temperature range (HOT) then getting
any kind of oil on the bulb will usually result in premature failure
due to a carbon hot spot, followed by deformation, followed by 
(often spectacular) destruction.  If anyone out there dosn't believe
that the quartz tube can deform, I have a few "neat looking" bulbs
that show quite nicely how well the quartz tube can deform.

                                        ...Rich
------------------------------------------------------------------------
Where: ..uunet!mnetor!yunexus!xrtll!rsnider    Also:  rsnider@xrtll.UUCP
An unbreakable tool is useful for breaking other tools.