Learning and Leading

BUYER’Sguide

Projectors allow even stu- dents in the very back of the room to see demonstrations, simulations, and anything else a teacher or classmate displays on a computer screen.

;ere was a time when projectors were expensive, large, and emitted a lot of heat. But lower prices, smaller models, and energy-e;cient units have led to increased use of projectors in classrooms.

Image clarity and brightness has also improved dramatically. Most projectors have lamp-based liquid crystal display (LCD) illumination. Lamp life can last for several thousand hours, but replacement bulbs are expensive, ranging from $150 to $700 each.

;e Sharp and Viewsonic units listed here are digital light processing (DLP) projectors that use thousands of microscopic mirrors to cast light. ;e newer light-emitting diode (LED) projectors have an electroluminescent light source. ;ey are environmentally friendlier, consuming as much as 30% less power, and they do not require costly bulb replacement. ;e Dell and Optima LED models listed are lightweight and e;cient but not as bright as the LCD models.

;e trend is toward ultra-portable projectors—as small as cell phones—that use solid-state and hybrid illumination.

Here are a few factors to keep in mind when selecting a projector:

The more lumens, the brighter the
image. A crucial factor in choosing
a projector is its brightness. Most
classrooms have windows without
shades, so a projector must provide
su;cient brightness to compensate
for the ambient light. ;e light
output of a projector is measured
in lumens. ;e American National
Standards Institute (ANSI) has
averaged several measurements,
making it easier to compare projec-
tors. Most of the models listed have
at least 2,500 ANSI lumens, and
schools can use them successfully
in rooms as large as an auditorium.