Password Magazine - Issue 31
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February 2008
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There are two main parts in a CFL: the gas-filled tube (also called
bulb or burner) and the ballast. Electrical energy in the form of an
electrical current from the ballast flows through the gas-filled
tube containing mercury molecules which have a special property:
when excited, they emit ultraviolet light. The ultraviolet light, in
turn, excites a phosphor coating on the inside of the tube and emits
visible light, which shines out through the tube. This phosphor
coating is a mixture of luminescent materials, each emitting a
different color. By changing the composition of the mixture, lamps
generating different grades of white light can be developed
(daylight, soft white, etc).
Making the CFL as reliable and high quality as the incandescent required a lot of research – and an electronics revolution. Early CFLs cost around $25 per bulb (although they still paid for themselves in electricity savings). The light they produced was bluish or pinkish so the phosphor coating had to be refined. The ballast hummed and didn’t cycle the electricity quickly enough therefore leading to a re-design to make it more electronic and miniaturized. Eventually, costs came down as did size. A popular concern about CFLs is that the technology underpinning the efficiency relies on a small amount of mercury to produce light. And while the concern is legitimate – and all exhausted CFLs must be properly recycled – a government-initiated study in Australia found that when you consider the mercury produced from burning fossil fuels for electricity, the energy-hungry incandescent contributes five times more mercury into the environment than a CFL. According to the US Environmental Protection Agency, coal-fired power plants emit four times more mercury to power an incandescent bulb than to power a CFL. Philips CFLs contain a record low amount of mercury – less than two milligrams, which is up to four times less than competitor CFLs. Philips also utilizes pellet dosing versus liquid mercury to ensure safe and accurate levels of mercury per bulb and continually looks for ways to reduce the amount of mercury while still maintaining light quality and performance. |
