A projector is an apparatus for presenting an enlarged image on a screen from a transparency such as a photographic slide or a film. In a motion picture projector, each frame is held stationary at an illuminated aperture for a brief period, and then advanced by an intermittent sprocket or reciprocating claw, the light being cut off by a rotating shutter during the movement. The soundtrack on the film is reproduced at a separate sound head where the film is moved continuously at a constant speed.

An average projector usually has a picture resolution of 800 x 600 pixels. Most of the projectors weigh four to six pounds and come with a carrying case. All of the projectors have varied brightness and contrast levels - usually the brightness varies from 1300 lumens to 1500 lumens. A projector with a brightness of 1400 lumens proves to be a good choice for small to medium-sized, well-lit rooms.

Some of the indispensable parts of a projector are the feed spool, xenon arc lamp, projection lens, optical sound head, take up spool, an aperture, normal lens and rotating shutter. But with the advancement of science, new technologies have come into play. The projectors have become much more advanced in terms of clarity of picture and quality of the pixels. Also, the projectors have found use in everyday households, as new versions of domestic projectors have arrived on the market. The abundance of LCD projectors, DLP projectors and video projectors has enabled the common man to enjoy the experience of a big theater hall in his living room.