Bulbs for Overhead Projectors

Overhead projector - Wikipedia, the free encyclopedia

August 29, 2013 – 10:09

Bulbs For Overhead Projectors ,For Sale,Prices,Manufacturers

An overhead projector is a variation of a projector for slides used to project images to an audience .

The overhead projector typically consists of a box containing a large lamp very bright and fan to cool it, on top of which there is a fresnel lens that focuses great light . On the housing, typically at the end of an arm length, there is a mirror , and a lens focusing and projecting the light back forward rather than up.

The slides are placed on top of the lens for exposure . The light from the lamp travels through the transparency and the mirror which projects forward on a screen for exhibition. The mirror allows the presenter and the audience see the image at the same time: the presenter looking down at the transparency as if writing, the audience look forward to the screen. The height of the mirror can be adjusted to focus the image and make it larger or smaller depending on how close it is the projector to the screen.

The best quality overhead projector offer enfermita wheel or screw adjustment in the body of the projector , the lamp to move toward or away from the lens fresnel . When the mirror on the lens moves too high or too low, moves the focal distance optimal to create a uniformly white image, resulting in a projected image of colored blue or brown that along the outside of the screen. Turning the adjustment wheel moves the lamp to correct the focal distance and restores the image projected on white .

The technology of an overhead lamp is usually very simple compared to the projector from a video modern LCD or DLP . Most use a projector lamp of extremely high power halogen that may consume up to 750 watts and yet produce a fairly weak, yellowish. It requires a high fan flow to keep the bulb without melting due to leakage of heat . Moreover, the intense heat generally fail quickly makes the halogen lamp, which often lasts for less than 100 hours before failing and require replacement. An LCD or DLP uses modern arc lamp with a higher luminous efficiency, and lasts for thousands of hours. One drawback to the technology of LCD / DLP is the heating time required for arc lamps, but that instant turn-on lamps halogen may be the biggest factor in their rapid rate of failure.

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Source: es.wikipedia.org

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Because the professors are stuck in their ways

The college professors are tenured and they are stuck in their ways, so they do not like change at all. They teach that the student must be open to change and reinvention of careers and knowledge, however, they still, like clockwork, buy the U.S.A. today newspaper and spread it out all over the toilet stall while they read the articles out loud pronouncing with care each syllable with gutteral accuracy and acumen.
The professors are slow to change and are still using overhead projectors instead of using computer generated information on the wall. However, there is a breakthrough, and this is the word "paperless

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  • Avatar Mommy of 2) Where can I find a projector for rent for my project? Not a movie projector.?
    Jul 17, 2008 by Mommy of 2) | Posted in Painting

    Like the ones they use in school that you put an image on and it shows it on the wall. NOT A MOVIE PROJECTOR. You think a library might have one??
    I want to paint a mural on my sons wall. I have found murals you can buy online and the one I like is 700 dollers. I printed in on a transparancy and tried to use a a lamp but that doesn't work..

    • You might be able to rent one from a business center. I have rented them for hotel conferences many years ago.
      Another option is to enlarge the image you have using the grid system. Draw grid lines in the original …transfer the image, drawing the shapes in each square. For example a 1/2 inch square on the orignal, would be a 6 inch square on the wall. That's the way a professional muralist would do it. That's the way I would do it.