Projector Terminology and Specs
1. Lumens- determines how bright the projector's bulb is.
- 1200 lumens is bright enough for classroom use if some of the lights can be turned off or the windows can be darkened.
- 2000 lumens is usually considered a threshold for leaving all the classroom lights on.
- A 3000 lumen projector is recommended for larger rooms (gymnasiums, media centers, cafeterias, auditoriums)
- 3500 lumens or higher would be recommended in a large room where windows can not be darkened
2. Inputs/Outputs- an projector has several inputs and outputs.
- VGA or RGB (15 pin computer cable)- this input will get the signal from
your computer into the projector.
- S-Video (4 pin video cable)- this input will receive the video signal from high-end VCRs, most DVD players, and
- RCA- standard composite video or audio cable which will transmit a video and audio signal from cameras, VCRs, and DVD
players to a projector. It is better to use an S-Video cable than an RCA cable. Also, most projectors have very
small speakers, so it is better to run the audio signal from VCRs, DVD players, etc. to a PA system.
- DVI- A high quality cable which will deliver a digital video signal from some computers, DVD players and satellite
receivers, especially those which process high definition signals. Always use this cable if your equipment has DVI connectors.
- USB- usually used to transfer control data from a computer to the projector. With this cable connected for instance, you can
often use the projector's remote control to act as a computer mouse and perform functions like advancing PowerPoint slides.
3. Resolution- determines the number of pixels that are present on a screen. More pixels will produce a sharper picture, but text
will be smaller at high resolutions, a factor which should be considered when using a projector where some viewers will be
located a long distance from the screen.
VGA- Video Graphics Array 640x480
SVGA- Super Video Graphics Array 800x600
XGA- extended Graphics Array 1024x768
4. Contrast Ratio- a number which expresses the difference between the brightest and darkest part of the same image. A higher
contrast ratio will normally produce more realistic pictures and video.
For example: a projector with a 400:1 contrast ratio will produce better images than a projector with 200:1 contrast ratio.
5. Bulb Life Meter- will tell you how many hours your projector has been used. With most projectors, spare bulbs should not be
purchased until the bulb life meter has reached 1500 hours (approximately 75% of a bulb's estimated 2000 hour life).