Page 257 - Electromechanical Devices and Components Illustrated Sourcebook

Chapter 12 Lighting 219

Type A Type PS Type B Type S Type G Type T Type C
Figure 12-30 Standard Light Bulb Shapes

1
or 3- / inch in diameter. A T10 is a cylindrical globe that is
8
1
1- / inch in diameter.
4
Like standard incandescent bulbs, flood and spotlights
have their own designators. Figure 12-31 shows a few of the
more common flood and spotlights that are available in the
market today.
Figure 12-32 shows designators and bulb shapes for mer-
cury vapor and high-pressure sodium lamps. It should be
Triple Quad Spiral Circular
noted that these bulbs are generally delivered with either
U-Tube Tube Tube Tube
admedium or mogul bases.
Figure 12-33 Screw Base Fluorescent Light Bulbs

Lamps that have an integral reflector fall into two different
categories, flood and spot. Flood lights generally have a
reflective surface behind the filament that is intended to reflect
the light that the filament generates at the back towards the
front of the lamp. The lens of the lamp acts a diffuser and is
Type BR Type ER Type R Type PAR
either frosted or carries a series of diffuser lenses, as shown in
Figure 12-31 Standard Flood and Spot Light Shapes
Figure 12-34.
Spot lights have a parabolic reflector that is intended to focus
a point source of light into a powerful beam. These types of
lights are available with an integral light bulb; however, they are

Mounting Flange

Mirrored Reflector
Diffuser Lens

Type BT Type E Type ET Type ED
Figure 12-32 Standard High-Intensity Discharge Lamp Terminals
Shapes Primary Lens

Compact fluorescent tubes are now commonly available in Filament
screw base packages, as shown in Figure 12-33. These lamps
are gaining popularity as high efficiency replacements for
their incandescent counterparts and can be purchased in any
hardware or home improvement store. Figure 12-34 Multilens Diffuser