a traditional piece of technology that passes a series of photographic slides inserted inside a carousel through a beam of light to be magnified and projected upon a vertical screen.
A slide projector is an opto-mechanical device to view photographic slides. It has four main elements: a fan-cooled electric light bulb or other light source, a reflector and "condensing" lens to direct the light to the slide, a holder for the slide and a focusing lens. A flat piece of heat absorbing glass is often placed in the light path between the condensing lens and the slide, to avoid damaging the latter.
