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
;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.
—Maureen Yoder, EdD, is on the faculty of
Lesley University’s Technology in Education