Among all the types of projectors available in the market Overhead projectors are the most common and widely used projectors. It is the perfect device that projects images to the audience with complete precision. The Overhead projectors have long been used as the teaching tools in schools and presentation tools for business purposes.

The overhead projectors are designed with a large box having a bright lamp and a fan to cool the components. The top of the box has large lens and a mirror is situated on the long arm above the box. This mirror shines the light forward instead of upwards. To project any image one has to put the transparencies above the lens. The bright lamp shines through the transparency and into the mirror. The image from here is projected on a display screen. The advantage of this projector is, the presenter and audience can view image at the same time and this is made possible due to the mirror. The spectator views the image through a projection screen whereas the presenter can see it by looking down at the transparency.

With the advent of digital and computerized technology the overhead projectors have come to a back foot, but those who still want to go for it can easily get this as they are still available in the market.