Lamp Guide: Incandescent
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.
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-19||A-21||A-23||B-10 1/2||B-13||BA-9||BA-9 1/2|