Overhead Projectors

Choosing an Overhead Projector

Whether teaching a class or presenting to your boss, an overhead projector allows you to improve your performance by sharing charts, graphs, pictures, and written material. There are more elaborate computer-based projectors available, but the overhead projector is still used due to its low cost and ease of use. Remember that you will have to purchase transparencies to use with the projector.

The type of content you are presenting and the location of the presentation will determine the technical specifications you should look for in an affordable overhead projector on eBay.

• Lenses come in three sizes: singlet, doublet, and triplet. Triplet provides the highest image quality but is also the most expensive.See the manufacturer site for details.
• Brightness is measured in lumens. When using the overhead projector in a dark room, 2000 lumens is sufficient. In a situation with more ambient light, you may need 2500 lumens. Look for higher brightness specifications for projecting complex or colorful images.
• Lamp type will give you an indication of brightness, lamp life, and heat production. An ENX lamp type has the longest life but lower lumens. An FXL bulb will produce more light but will also run hotter and have a shorter life.
• Heads can be open or closed to protect from dust and fingerprints. Closed heads are more expensive.

A basic overhead projector consists of a box with a lamp and a mirror on an adjustable arm. Some models also have special features to improve performance.

• An automatic lamp changer replaces a burned out bulb without pausing your presentation.
• Color tuning adjusts lamp brightness to optimize colors.
• A lamp high/low switch allows the user to maximize lamp life by lowering brightness when it is not needed.

An overhead projector shines a light through a transparent sheet and reflects that image onto a wall or screen. A document camera takes a picture of a paper or object and projects the picture onto a wall or screen. Document cameras are versatile, and overhead projectors are less expensive and easy to use.

If you are on a budget or only need to use it for a limited time, look on eBay for a used overhead projector. You might also buy a used overhead projector for repair and replacement parts.