DIY-Projector Plans and theory collection !!

[ace3000_1]

mathias put a peice of paper infront of the torches reflector, without its lens on and see what pattern u get on the paper with the paper standing on its end. Its parabolic.

As ive said you can also test this with your finger.

In the picture below these are all parabolic reflectors, the one on the left and center is a 25deg spot light, the one on the far right is a torch reflector, they are all the same shape and are parabolic.

And mathias im not arguing im stateing facts.

[ace3000_1]

And here we have big brother and little sister, the big brother is a halogen par spot 30deg spot light, ring a bell mathias? these are the same shape on all reflectors.

Trev

[Hezz]

Guys,

The fact of the matter is that there are differing shapes of both parabolics and elliptical reflectors. Both kinds can be made shallow or deep. The difference is that they follow a different mathmatical formula for how the slope of the curve changes. It is possible to make an elliptical reflector that is so close in shape to a similar parabolic that it would be hard to tell at a casual glance which is which. You would have to have them superimposed on each other to tell the difference.


Hezz

[ace3000_1]

Hezz ive just tested my torch out, its parabolic for sure, all of the other parabolics that i have and are known parabolics share the same shape, and thats why i have taken the pictures and posted them up, your right about the depth factor and this is normally used in area size and focal lengthes given to a certian the aplication can fit into, it also has alot to do with eficientcy.

Trev

[mathias]

Trev, you really got me to laugh All those reflectors you show are exectly what I am talking about, they have a scape close to a ellipse, but they are called parabolic anyway. If you try to draw a circle over them you will notice what it´s impossible.

[ace3000_1]

mathias i dont understad you somtimes, these are parabolic reflectors, not eliptical and no way can they work in the same way, sure they will come close, but its ineficient and they arent designed to do so, if they did well then they wouldnt have made a parabolic reflector and a eliptical would they? Its imposible to turn a parabolic reflector into an eliptical. However you can turn a spherical to radiate parabolic light rays, but its not eficient and thats why we have a parabolic reflector with its acociated shape designed to work in an eficient manner.


Trev

[ace3000_1]

If you try to draw a circle over them you will notice what it´s impossible.

I know this but look at your drawings, they are half round when they shouldnt be.

[mathias]

Trev you must agree that the ellipse is closer in my torchreflector picture than the circle even if it´half round, that´s why I called this kind of reflectors elliptical, but as Hezz say it´s very hard to see the diffrence. Anyway it´s good that we are talking about the same type of reflectors, I would maybe called it "deep parabolic reflectors".

[ace3000_1]

Yeah somthing like that lol, hey i just tried a parabolic with a condenser, no go , you will end up with a dark patch in the middle, i turned the condenser around the oposite direction also and basically you will loose light so a pcx on a parabolic is a no no and its why they arent comonly used at all on parabolics, this is where an eliptical has another advantage cos with an eliptical we can use a condenser of this nature because it has a focal point. In magna lights i think they use a double convex lens so its probally more the go on a parabolic system.

Trev

[mathias]

I just want to show the difference between a real parabolic reflector and a elictical/parabolic reflector. The reflector to the right is a true and orignal parabolic reflector, to the left the deep parabolic or eliptical reflector or what you want to call it. In my design where I say eliptical I mean the deep parabolicreflector. This is the type of reflector you must use in the slideprojector design.

If you want to build the slideprojector design, which is the absolute best design use condensors from a slideprojector and turn them in the way they are in the slide-pj. You maybe need bigger slideprojectorcondensors but they must have the same scape as the orginal slideprojector condensors.

Also with slideprojector I mean whose how use a ELC A1/259 multimirror bulb 150-250W.