It is an optical device (which means it deals with light) which project image. It enlarges the image size. The images can be static like data or graphical or moving image (video). Projector does this by passing the image to be projected through a lens which enlarges the image. In this article we discuss the digital projector.


Functions of a projector

  1. Presentation

There main use is for presentation of content. The presentation can be done by different people in different professionals. A lecturer can use a projector to present note to his student in a classroom. A manager can use it also to present the company growth over the past year and so on. So in general a projector can be used by any person who wants to communicate to a large group of people. Today almost every company and business enterprise owns a projector for presentation.

The presentation can be creates using variety of presentation software in the market. They offer the use with ways of creating slides which can be used to represent an ideal per slide.

  1. Clarity of data or information

Projector can also be used to enlarge images which are small and viewing them directly will strain the eyes and won`t give the required information. Example an object from a scene of crime can be projected to try and get the information that inscribed on a surface.

  1. Watching movies

Projectors are used in movie theaters to enlarge the movie on a larger surface. This allows more people watch the same movie.

Type of projectors

There are 3 types that are used today depending on the technology that they use.

a) LCD projectors: they are also known as 3LCD because they use light is passed through 3 LCD panels before it is projected on the surface. These are the most common type of projectors. They are advanced from the slide projector that were used to project small image to enlarge them. They are small and better performance than the slide projectors.

b) DLP projectors: Digital Light Processing projectors. It is made up of DLP chip which composed of many micro-mirrors. The light is reflected off these mirrors through a lens and onto the projection surface. The mirrors are movable and can be used to display different colours.

c) LCoS projectors: Liquid Crystal on Silicon. The liquid crystals are arranged in silicon. The light is then passed through the silicon the to the projection screen. They are better than other but they are more expensive.

d) LED projectors: these projectors can use any of the other technology but the source of light is Light Emitting Diode instead of lamp that is used by the other. Also some projector that use laser beam are in use today.

Factor to consider when selecting a projector


The weight of the projector may be considered if you intend to be carrying it around. If you intend to use it as fixed projector then weight may not matter that much. LCD projector are known to be a bit heavy than DLP.


It is one factor that you cannot ignore. It is the measure of number of dots per inch that the projector can give (dots per square inch). The higher the number of dots the better the image clarity. A 1024 X 768 is good for detail presentation. Again the resolution may be affected by the source of data resolution. If the source of data has a high the overall resolution will be good.


Depending with the budget that you have for the projector that you want, you can get varying prices. Follow your budget, but remember sometime cheap may end up being expensive.

Brightness and contrast

Brightness is measured in lumens. Higher numbers of lumens are better, for bigger room which needs more light. For smaller room around 800 lumens is good brightness.

Contrast is the different between the bright and dark part of the image. The high the ratio the clearer is the image. Select a projector with high contrast ratio.

Lamp life

For the projector that uses lamp as source of light you may want to consider the life of the lamp. Choose a projector that has a high lamp life because to replace a new lamp will mean extra cost.


Different projector comes with different way of connecting to the source of data. They include USB, WIFI, VGA, HDMI and DVI. Choose one that offer more than one way of connecting to the source.

Type of projector

Depending with the preference one may want to consider a projector type and manufacturer.

Connecting projector to laptop

Connect the projector to the power source, and then connect the VGA cable on one side to the laptop and the other side to the projector VGA port. Tighten the cables to the ports by screwing the screws on the cable. Press the power button on the projector to switch it on. When the projector is fully on and ready the light on “ON button” should be turn to green.

When using laptop the VGA cable should be connected to the port labeled INPUT and not MONITOR. After the connection the projection is by now suppose to be that on the laptop.

If no display yet you can either use the FN key with one of the function key with a symbol of a monitor (the function key with the symbol may vary from one laptop to another)or go to laptop control panel then display and click on connect to the projector it will give you options (for those using Windows). It give the option of view from laptop screen alone, both projector and laptop screen and projector only. Below image show option offered in Window 7.

window projector setting

After connection the next thing that you can do to get the best image is use the function on the projector, like to focus the image, increase brightness and the like. With that you will be ready to go. Make sure you laptop is not set to go on sleep mode of have a screen saver because most of the time it may interrupt you presentation, it is not professional.