Incandescent Light Bulb Diagram


A) Bulb: Soft glass is generally used. Hard glass is used for some lamps to withstand higher bulb temperatures and for added protection against bulb breakage due to moisture. Bulbs are made in various shapes and finishes. Click to view various incandescent light bulb shapes.

B) Filament: The filament material is generally tungsten. The filament may be a straight wire, a coil or a coiled-coil. Click to see various types of filaments and sample products that use the filaments.

C) Lead-In Wires: Made of copper from base to stem press and nickel-plated copper or nickel from stem press to filament, they carry the current to the filament.

D) Tie Wires: Molybdenum wires support lead-in wires.

E) Stem Press: The lead-in wires in the glass have an air tight seal here and are made of a nickel-iron alloy core and a copper sleeve (Dumet wire) to assure about the same coefficient of expansion as the glass.

F) Exhaust Tubes: Air is exhausted out of and inert gases are introduced into the bulb through this tube during manufacturing. The tube, which originally projects beyond the bulb, is then sealed off short enough to be capped by the base.

G) Base: This is where electrical contact is made. One lead-in wire is soldered to the center contact and the other soldered or welded to the upper rim of the base shell. Made of brass or aluminum. Click here to view various base types and some sample light bulbs that use the bases.

H) Gas: A mixture of nitrogen and argon is used in most lamps 40 watts and over. Gas slows down the evaporation of the filament.

I) Support Wires: Molybdenum wires support the filament.

J) Button: Glass is heated during manufacturing and support and tie wires placed in it.

K) Button Rod: Glass rod supports the button.

L) Heat Deflector: Used in higher wattage general service lamps and other types when needed to reduce circulation of hot gasses into neck of bulb.

M) Fuse: Protects the lamp and circuit by blowing if the filament arcs.

GoodMart sells many incandecent light bulbs. Choose from the list below to view our available incandescent light bulbs:
15W-40W A-Shape Incandescent Light Bulbs 50W-75W A-Shape Incandescent Light Bulbs 100W-200W A-Shape Incandescent Light Bulbs Torpedo Bulbs C Bulbs Globe Lamps PAR Bulbs Incandescent Reflector Bulbs Tube Lamps Straight Sided S Shape Lamps Traffic Light Bulbs