Hmmmm Me thinks thou doth protest too much !
See now I was going to
point out that pretty mch all lamps from the ones in your
house up to the
hpl in you s4's are all
tungsten lamps, in that they all use
tungsten as a
filament. Early on
Edison < or his lackeys> expirented with all sorts of materials until they finally found
tungsten to be the strongest longest lasting
filament that was
practical for use in the
incandescent light
bulb.
Incandescent is your first clue as to the difference between an
incandescent and arc lamp. in an
incandescent lamp the
filament glows white hot thus producing light or incandescening. This process is no different than heating a stick of
iron in a furnace until it glows, except the energy is provided by electrical resistance rather than coal burning < 'course if you are in an area of the country where they use coal fired electrical plants I guess you could say it really is no different at all
> An Arc lamp Typically uses a much higher
voltage so that a "spark" or arc is maintained across a gap between two electrodes. Go drag your feet across the carpet then touch your sisters nose, Viola'! You just created an arc, light emitted by the excitation of a gas < air > by a High
voltage low amperage
current jumping between two points of space, you finger her nose, < now say you're sorry, Van made you do it>
Now an arc lamp in a ML is basically the same thing if you look closely you'll see an outer
envelope and an inner one. Ignore the outer one it's boring. The cool part is the inner one where you'll notice there is no connection between the two
wire thingys comming in from each end of the
envelope. Now it's quite possible those electrodes are made of
Tungsten < ship help me out here > but the important thing is that the
envelope is full of gas. Different types of lamps use different types of gas,
mercury vapor,
sodium vapor, All the
halogen gases < those are the ones over on the right side of the periodic table of elements> Different gasses will all "glow" or incandesce at different wavelengths resulting in the different "color temperatures" of various lamps. The advantage of Arc lamps is thier high color temperatures, that is they are very white. if you look at the thread going on right now about
CMY versus RBG color mixing you'll see why it's important that in a Moving light where
CMY mixing is employed it is very important that your "source light" be as close to pute white as possible, whereas in a S4 which youtypically employee in the RBG mixing method you can get away with a cooler
color temperature.
Now there are a ton more things about
Tungsten Halide lamps that are interesting and you can look up some of Ships old posts to look into those, He's a real expert I'm a hack when it comes to stuff like this. Hope that helps and anybody feel free to expand or slam what I just posted.
essay question for extra credit:
What are the main differences between light
bulb in your
house and an
HPL in your S4, if they both use a
tungsten filament ?
