Incandescent Lamps

A Short History
The first incandescent lamp was introduced on October 21,1879, by Thomas Edison. The original bulb used a carbon filament in a bulb containing a vacuum. Modern bulbs now primarily use tungsten filaments with a gas fill instead of a vacuum, though bulbs using thin filaments and lower currents still utilize a vacuum because they function more efficiently.

The Filament
The filament acts as a resistor. An electric current passes through the filament, and resistance in the filament causes it to heat and incandesce. Filaments typically reach temperatures well over 2000 degrees Celsius.
Most of the energy consumed by the bulb is given off as heat, causing its Lumens per Watt (LPW) performance to be low. Because of the filament's high temperature, the tungsten tends to evaporate and collect on the sides of the bulb. The inherent imperfections in the filament causes it to become thinner unevenly. When a bulb is turned on, the sudden surge of energy can cause the filament to break, because the thin areas heat up so much faster than the rest of the filament, leading to bulb failure.

Quality of Light
Incandescent lamps exhibit smooth, even spectral power distribution (SPD) because they use the heat of a solid object to produce light. Incandescent lamps also score very high on CRI ratings, but because standard incandescent lamps produce very little radiant energy in the short wavelength end of the spectrum, they do not render blues very well.

The Upside
The low color temperature combined with a high CRI casts a warm light which provides excellent color rendition of skin tones. In addition, incandescent lamps are affordable, can be controlled by dimming circuits, and are available in a wide range of sizes, configurations and wattages.

The Products
15-40W Standard Shape Bulbs (A Line) 50-75W Standard Shape Bulbs (A Line) 100-200W Standard Shape Bulbs (A Line) B10 (Torpedo Shape) Cone Shape "C" Globe Shape Incandescent PAR Bulbs Incandescent Reflector Bulbs Specialty Lamps Tube Shape-Exit Sign Lamps Straight Sided Shape-"S"