Digital projectors are common hardware output devices used mainly in business and educational settings, as well as for entertainment. Data projectors project an image onto a screen or wall. Most of the specifications used for screens are used for projectors (resolution, contrast ratio, connections) as well as brightness, measured in lumens.
The bulb of a projector is capable of projecting intense (very bright) white light. The intensity of this light is measured in lumens. Next time you are at the supermarket, have a look at the torches on sale: they will most likely have a rating in lumens — 200 to 300 lumens would be a pretty bright hand torch. Most data projectors sport light bulbs rated 2000 or more lumens!
Most projectors connect via HDMI these days. A slightly older projector will connect via VGA (most projectors will have VGA and HDMI ports). A VGA cable can only transmit video (picture) data whilst an HDMI cable can transmit video and audio (sound) data. HDMI is also capable of transmitting data at a far faster rate than VGA.
More advanced projectors will have the ability to connect wirelessly and/or using an Ethernet cable.
The resolution of a projector, which is largely responsible for the quality of the image, is measured in the same manner as a screen: the number of pixels across by the number of pixels down, for example, 1920 x 1080.
- Can display picture to a large group of people.
- Not as bright as a monitor so the room must be darkened.
- Does not offer the same clarity as a high-resolution monitor.
- Not suited to a small venue (needs to be a minimum distance from the surface it is to be projected onto).
- Lower resolution than a high-end monitor.
- Aspect ration not always suitable for certain uses, e.g. widescreen movies.
- Lower contrast ratio than a monitor