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.
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| C-2V CC-2V |
C-5 | C-6 CC-6 |
CC-6 | C-7A | C-8 |
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| 2CC-8 | C-9 | C-11 CC-11 |
C-13 CC-13 |
C-17A | C-2R CC-2R |
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| MP | BP | FF | M | SC | CC-6 |
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| CC-8 |
Incandescent Base Types
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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 | |||||||
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| A-19 | A-21 | A-23 | B-10 1/2 | B-13 | BA-9 | BA-9 1/2 | |||
| BR | C | ER | |||||||
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| BR-19 | BR-25 | BR-30 | BR-40 | C-7 | ER-30 | ||||
| F | G | K | P | ||||||
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| F-10 | F-15 | F-20 | G-16 1/2 | G-25 | G-40 | K-19 | P-25 | ||
| PAR | PS | ||||||||
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| PAR-16 | PAR-20 | PAR-30S | PAR-30L | PAR-36 | PAR-38 | PAR-64 | PAR-64 | PS-35 | |
| R | RP | S | |||||||
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| R-20 | R-30 | R-40 | R-40 | RP-11 | S-6 | S-11 | S-14 | ||
| T | |||||||||
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| T-4 1/2 | T-5 | T-6 | T-8 | T-8 | T-10 | ||||