Projection Devices, Continued
Slide projectors Slide projectors are the most common still picture projectors found in
military commands. The operation of slide projectors is simple and
universal. These projectors project an image from 35mm or 126mm, slide
film in a 2- by-2-inch slide mount. Some projectors can project super slide
film in the 127mm format. Slide projectors are used in teaching, briefing,
and as a draftsman’s aid in enlarging images. The limitations of a slide
projector are that the feed mechanism easily jams, and the bulb is very
sensitive to rapid temperature fluctuations and perspiration from your hand
during handling.
Nomenclature
Although the slide projector looks difficult to adjust, its many parts have
obvious functions. A slide projector consists of a slide holder, lens, focusing
knob, forward/reverse button, on/off button, select button, remote receptacle,
dissolve receptacle, timer, and a bulb. Some of these features require further
explanation:
SLIDE HOLDER: The holder for slides fed into the slide projector is
available as a tray that holds from 60 to 180 slides or a stack loader that
feeds a stack of slides one at a time into the projector.
SELECT BUTTON: Use the select button to select a specific slide in the
slide tray. Depress SELECT and spin the tray to align the slide sequence
number with the gate. When you release the SELECT button, the desired
slide will advance into the gate for projection.
TIMER: Use the timer button to select the manual or automatic mode. In
manual, the operator has control of the amount of time the slide is on the
screen. In automatic, the operator selects the time interval and the projector
automatically changes the slide. The timer activates to prompt the projector
to change slides and refocus. The choices are in 5-, 10-, and 15-second
increments.
BULB: The bulb in a slide projector has two levels of illumination. Low
illumination is 425 watts. Using the projector bulb at low watt illumination
prolongs the life of the bulb. High illumination is 500 watts.
Continued on next page
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