Are these projectors a thing of the past?
Overhead projectors are useful tools for assisting in classroom lessons, presentations, and lectures. They enable you to give examples, show key points and diagrams in an efficient and interesting manner. They can give you extra scope for explaining any rising questions within your group while maintaining eye contact and good communication skills.
Preparations are written on acetate, transparent plastic sheets, which are cheap and easily replaced. Overhead projectors are simple to use and do not need any extra equipment such as special screens on which to project, a plain wall or white board will do.
How do they work?
These projectors work by collimating light rays which are then reflected off a mirror which is redirected forward by a light. Overheads need plugs to activate them so remember to check out the location of sockets and provide an extension cable if necessary. Always bring several sheets of spare acetate incase you have an unexpected rush of questions which need backing up with diagrams and explanations. Spare projector bulbs are always handy to bring along as no one wants to go through the humiliation of losing a major focus of their presentation.
When writing on the acetate, be sure to use a water based pen so the ink can be erased and the acetate used again. This is a major bonus of the overhead as your lectures or presentations can almost be improvised if this feature is used to full advantage.
The switching on and off of the projector can also stimulate drooping concentration and can be used as a way of giving a definite end to a section or lesson.
However, despite the above advantages, with the development of LCD projectors and DLP projectors, overheads will eventually become a thing of the past. They are awkward to transport and the constant replacement of acetate becomes expensive and tiresome. There is a facility for enlarging the print on the projected text but this becomes a little cumbersome to use and it may be necessary to have to shunt the entire overhead projector around before finding a clear image.
Choice of Overhead Projectors
There are several types of overhead projectors to choose from:
Portable projectors, cost effective projectors and high performance projectors. The brightness of a projector is measured in ANSI Lumens, the brighter the light, the more expensive the projectors are. The most basic designs begin at $35 and are designed for small businesses or educational needs. The more complex design may have a double lens with a higher resolution, a substantially quieter fan which reduces annoying noise and extra features such as pen holders. These are priced over $200.
There is a projector which is able to display opaque materials in day lit rooms such as magazines and brochures using treated high quality optics. This widens the range of visual aids when giving presentations and they are relatively uncommon thus maintaining the interest of your audience. Their price begins at over $1400 so this tool is only likely to be used by larger businesses.