|
the science The incandescent bulb gets its name from the process by which light is generated. Incandescence produces artificial light by passing an electrical current through a filament usually made of tungsten, causing it to heat and emit light. The filament is contained within a glass enclosure ('bulb') which is filled with an inert gas at a low pressure or a vacuum. The vacuum or inert gas prevents the filament from combusting and burning out. Incandescent bulbs waste about 90% of the power they consume in heat and are therefore about 10% efficient. Bulbs are usually marketed according to the power consumed; this is measured in watts and depends mainly on the filament's resistance. It is difficult to predict the light output based on a watts-consumed figure as light output is typically measured in lumens. A typical filament bulb will last approximately 1,000 hours when used in normal operation. However, the glass content and the delicate filament makes the incandescent bulb intolerant of vibration and physical shock during its lifetime.  |
 |
the
facts Solid state lighting90% efficiencyRobust construction 50,000 hours lifeNo IR or UV emissions |
