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Lamp Guide: Incandesent

Incandescent Filament Designations

Filament designations consist of a letter or letters to indicate how the wire is coiled, and an arbitrary number sometimes followed by a letter to indicate the arrangement of the filament on the supports. Prefix letters include C (coil) -- Wire is would into a helical coil or may be deeply fluted; CC (coiled coil) -- wire is would into a helical coil and this coiled wire again wound into a helical coil. some of the more commonly used types of filament arrangements are illustrated.


C-2V CC-2V	C-5	C-6 CC-6	CC-6	C-7A	C-8

2CC-8	C-9	C-11 CC-11	C-13 CC-13	C-17A	C-2R CC-2R

MP	BP	FF	M	SC	CC-6

CC-8

Incandescent Base Types

Incandescent Bulb Shapes

The size and shape of a bulb is designated by a letter or letters followed by a number. The letter indicates the shape of the bulb while the number indicates the diameter of the bulb in eighths of an inch. For example "T-10" indicates a tubular shaped bulb having a diameter of 10/8 or 1 1/4 inches. The following illustrations show some of the more popular bulb shapes and sizes.

A				B			BA

A-19	A-21	A-23		B-10 1/2	B-13		BA-9	BA-9 1/2

BR					C		ER

BR-19	BR-25	BR-30	BR-40		C-7		ER-30

F				G				K	P

F-10	F-15	F-20		G-16 1/2	G-25	G-40		K-19	P-25

PAR									PS

PAR-16	PAR-20	PAR-30S	PAR-30L	PAR-36	PAR-38	PAR-64	PAR-64		PS-35

R					RP		S

R-20	R-30	R-40	R-40		RP-11		S-6	S-11	S-14

T

T-4 1/2	T-5	T-6	T-8	T-8	T-10