Then the invention of ductile tungsten, a much improved filament material, sparked the development of the modern tungsten filament incandescent light bulb by the General Electric Company and William Coolidge in 1906-10. This is the light bulb we know today. Ductile tungsten has many favorable properties such as a high melting point: 3,410 oC / 6,170 oF low evaporation rate at high temperatures: 10-4 torr at 2,757 oC / 4,995 oF tensile strength greater than steel Because of its strength, ductility and workability, tungsten can readily be formed into the filament coils, used to enhance performance in modern incandescent bulbs. Due to its high melting point, tungsten can be heated to 3000oC / 5,432 oF, where it glows white hot providing very good brightness. However, the early tungsten filaments still sublimed too quickly at such high temperatures. As they sublimed, they also coated the bulbs with a thin black tungsten film, reducing their light output. Inert gases such as nitrogen and argon were later added to bulbs to reduce tungsten evaporation, or sublimation. While these gases reduced evaporation and increased filament life, they also carried heat away from the filament, reducing its temperature and brightness. Winding the wires into fine coils, as used in modern incandescent filaments, reduced convective heat loss, allowing the filament to operate at the desired temperatures.

Modern incandescent bulbs are not energy efficient, only four to six percent of the electrical power supplied to the bulb is converted into visible light. The remaining energy is lost as heat. However these inefficient light bulbs are still widely used today due to many advantages such as: wide, low-cost availability easy incorporation into electrical systems adaptable for small systems low voltage operation, such as in battery powered devices wide shape and size availability