Page 255 - Electromechanical Devices and Components Illustrated Sourcebook

Chapter 12 Lighting 217

Miniature Candelabra Intermediate Medium Medium Skirt Admedium Mogul
Figure 12-20 Standard Screw Bases

Bayonet bases are common in automotive and instrumen- Opaque Coating
tation applications. Figure 12-21 shows both double contact
and single contact bases. The double contacts are generally
reserved for dual-filament lamps, such as automotive tail
lamps. One filament is for running lights while the second,
Bulb
brighter, filament is for brakes.

Ceramic Base

Pins
Double Contact Single Contact
(DC) (SC) Figure 12-23 Two-Pin Base
Figure 12-21 Standard Bayonet Bases

Flange
Bulb
Bulb
Insulator
Terminal
Groove
Terminal
Insulator
Terminal Terminal
Figure 12-22 Flanged Base Figure 12-24 Grooved Base

The flanged base bulb, shown in Figure 12-22, is typically Sealed beams, most commonly used in automotive, con-
used in flash lights and indicator applications. The bulb is struction equipment, and marine applications, use one of four
dropped into the socket and a screw-on cap is used to secure different base configurations. Figure 12-25 shows the typical
it in place. base patterns for sealed beams. The two- and three-lug types
Two-pin bases, as shown in Figure 12-23, are typically found are usually used with a standard connector. The space lugs
on high intensity lamps, such as halogen units. These bases are are used with standard crimp-on connectors and the screw
commonly found in projection and audio visual equipment. terminals are for connecting to either stripped wire or screw
Grooved base bulbs are used in applications that require a lugs.
very small incandescent bulb. These lamps snap into place Fluorescent tubes are most commonly supplied with either
and are retained with a spring loaded detent. Figure 12-24 medium bi-pin or single pin bases, as shown in Figure 12-26.
shows a typical grooved base bulb. The recessed double contact is typically found in industrial

Two Lug Three Lug Spade Lugs Screw Terminals
Figure 12-25 Sealed Beam Bases