Bulb Type
Incandescent and Halogen
The incandescent light bulb uses a glowing wire filament (Tungsten) heated to white-hot by electrical resistance, to generate light. With time the filament evaporates and bulb efficacy is reduced.
Tungsten halogen bulbs are a refinement of incandescent technology. The halogen gas inside a halogen lamp causes the evaporated tungsten to redeposit on the filament. This process, along with high pressure inside the capsule, slows down deterioration of the filament, improves lumen maintenance and extends the lamp’s service life. In brief: higher and longer efficacy and light output, whiter colour are the main features of a halogen bulb.
Fluorescent Bulb
A fluorescent bulb is a “gaseous discharge” light source. Light is produced by passing an electric arc between tungsten cathodes in a tube filled with a low pressure mercury vapor and other gases. The arc excites the mercury vapor which generates radiant energy, primarily in the ultraviolet range. This energy causes the phosphor coating on the inside of the tube to “fluoresce,” converting the ultraviolet into visible light.
LED
LEDs differ radically from traditional light sources in that there are no glass bulbs or filaments to break, or electrodes to decay. Instead, LEDs are solid state light sources – basically, a chemical chip embedded in a plastic capsule. When the chip is energized by applying a voltage, it emits visible light, the color depending on the chip’s chemical composition.
Information from Natural Resources Canada - Lighting Reference Guide
