Table:  Filaments

FilamentShape Description Link
C2L1Carbon, two loops, one support
C3L0Carbon, three loops, no supports
C3L2Carbon, 3 loops, 2 supports
C4L0Carbon, four loops, no supports
C4L3Carbon, four loops, three supports
CL1Low voltage carbon, one loop
CL2Low voltage carbon, two loops
CL2L1Low voltage carbon, two loops, one support
CL5Low voltage carbon, five loops
CLxCarbon, small bulb, no supports, x loops
CxLyCarbon. x loops and y supports
R0No supports
R1Short, quarter-circle, 2 supports, "Coiled Coil"
R1AShort, quarter-circle, 1 support (usually lower voltage)
R1BOne support, Λ shape
R1N2 supports, forms a "N" or "И" when seen from above
R2Three-quarters circle, 5-6 supports
R2CTwo supports, П shape
R2XR2 with one bend toward center, W-shaped
R3Up-and-down zig-zag around the central post
R3CUp-and-down zig-zag concentrated in center, projection bulbs (C-5)
R3½Like R3, but the supports come from two different points on the center post
R4Short height squirrel-cage
R4D"Dutch", two tiers, essentially two R2s in series.
R4XR4 with three tiers of supports.
R5Up-down spiral, suspended from glass cross-beams, projection bulbs
R5HHorizontal double spiral, possibly suspended from glass cross-beams, projection bulbs
RBSquare spiral forming block
RL0Low voltage, no supports, as in a flashlight bulb
RL0SOne of the leads goes up to bulb tip for centering
RL1Low voltage, one support, Λ shape
RL2Low voltage, two supports, П shape
RL2XLow voltage, two supports, X shape
RL3Three supports, up-down-up-down
RLV0Low voltage, no supports, vertical
RTLong straight for tubular bulbs
RV0Vertical, no supports
RV1Vertical, one support
RZ1One-way zig-zag
RZ2Up-down zig-zag
RZ4Up-down-up-down, for a European antique look
SQ3Squirrel Cage, all supports from one glass bead
SQ4Regular Squirrel Cage, two sets of supports, two glass beads