A projector is an output device that projects an image onto a large surface, such as a white screen or wall. It may be used an alternative to a monitor or television when showing video or images to a large group of people.
Projectors come in many shapes and sizes though they are commonly about a foot long and wide and a few inches tall. They can be mounted on ceilings or may be freestanding and portable. Ceiling-mounted projectors are typically larger, especially ones that project a long distance (such as 30 feet or more). These projectors are commonly found in classrooms, conference rooms, auditoriums, and places of worship.
Portable projectors can used wherever there is a bright surface (such as a white or light colored wall). Most projectors have multiple input sources, such as HDMI ports for newer equipment and VGA ports for older devices. Some projectors support Wi-Fi and Bluetooth as well.
Front vs Rear Projection
Most projectors can be used for either front or rear projection. The difference is the screen, which is opaque white for front projection and semi-transparent grey for rear projection. Front projection sends the image from the position of the audience to the front of the screen. This is by far the most common method since it does not require an empty space behind the screen.
Rear projection projects the image towards the audience from behind the screen. This method is less affected by ambient light and often provides better contrast. Rear projection is commonly used in outdoor settings and commercial areas where space is not an issue.