Overhead Projector
Overhead projector is
a tool used to display images on a screen or wall. It consists of a large box which
contains a halogen lamp and a fan to cool it. On top of the box there is a large
lens called Fresnel lens that makes rays of light parallel. Above the box,
there is a long arm that has a mirror to catch and redirect the light towards
the screen or wall, and an adjustment wheel which is used to control image
focus.
- Place the projector on a flat surface
- Connect the power cord to a power switch and switch on the power
- Place transparency on the Fresnel lens
- Adjust the focus and screen alignment using the wheel
Advantages of an overhead projector
- Overhead projector transparencies are handmade and we can easily fix these if anything goes wrong.
- One can easily take overhead projector transparency out of sequence.
- One can write on and amend overhead projector transparencies on the fly.
- The presenter/ teacher can maintain eye contact while using an overhead projector.
Types of projector
Slide projector-These types of projectors use photographic slides to display images on a screen or wall.
Slide projector-These types of projectors use photographic slides to display images on a screen or wall.
DLP (Digital Light Processing) projector-DLP projector generates light from Mercury bulb and then sent it through a prism containing millions of micromirrors to display images on a screen or a wall.
Digital projector-Digital projector is a computer display system that when connected to digital image source like laptop, digital camera, or HD recorder, displays an enlarged image on a screen or a wall.
UNIT-101