Incandescent light bulb granted a Hungarian patent (No. 34541) for a tungsten filament lamp that lasted longer and gave brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1904. This type is often called Tungsram-bulbs in many European countries. Filling a bulb with an inert gas such as argon or nitrogen slows down the evaporation of the tungsten filament compared to operating it in a vacuum. This allows for greater temperatures and therefore greater efficacy with less reduction in filament life. In 1906, William D. Coolidge developed a method of making "ductile tungsten" from
Phase-out of incandescent light bulbs potentially visually-obstructive snow and ice on warning lights and signs. The heat is also used to melt the wax inside lava lamps. Some CFLs may not be compatible with existing dimming circuits such as those using TRIACs, although more dimmable CFLs are expected to become available as the phase-outs continue. Mains voltage halogen bulbs provide a somewhat more efficient dimmable alternative to common incandescent bulbs and are readily available, although they too will be phased out in the EU from September 2018. Dimmable LED lamps are available from several vendors, although not all LED lamps are compatible with dimmers and