exposes the filament to view. These lamps are used with
Rating
reflecting equipment that completely conceals the lamps
to avoid glare. Clear lamps can be used with
Incandescent lamps are rated in watts, amperes,
volts, candlepower, or lumens, depending on their type.
open-bottom reflecting equipment when the units are
Generally, large lamps are rated in volts, watts, and
mounted sufficiently high so that the lamps will be out
lumens. Miniature lamps are rated in amperes for a
of the line of vision.
given single voltage and in candlepower for a
The inside frosted lamp consists of a glass bulb that
voltage-range rating.
has the entire inside surface coated with a frosting. The
frosting conceals the filament and diffuses the light
Classification
emitted from the lamp. These lamps can be used with or
without reflecting equipment.
Standard incandescent lamps are classified
according to their shape of the bulb, finish of the bulb,
The silvered bowl lamp is provided with a glass
and type of base.
globe that has a coating of mirror silver on the lower
half. The coating shields the filament and provides a
BULB SHAPE.-- The classification of lamps
highly efficient reflecting surface. The upper portion of
according to the shape of the bulb with the
the bulb is inside frosted to eliminate shadows of the
corresponding letter designation is illustrated in figure
fixture supports. These lamps are used with units that
4-5. The designation letter, which denotes the shape of
are designed for indirect lighting systems.
the bulb, is followed by a numeral (not shown) that
denotes the diameter of the bulb in eighths of an inch
The colored lamp may consist of a colored glass
bulb. These lamps are used for battle and general
BULB FINISH.-- The clear lamp consists of a bulb
lighting and for safety lights.
that is made of unclouded or luminous glass, which
Figure 4-5.--Classification of lamps according to the shape of the bulb.
4-5
