Categories
Misc.
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What are the differences in light bulbs and how do you choose the right one?
So
many new products come out each year and they frequently rave about a
feature that most of us haven’t heard of or just don’t know much about.
Just
a few years ago the choice was very simple, you figured out if you
needed a 60 watt or 75 watt standard incandescent bulb and brought it
home.
Now there are these other choices and they have letters instead of full names like CFLs, and LEDs.
Here is a breakdown of the different types of light bulbs and what they do for you:
Standard
Incandescent Light bulbs- These have been around since 1879 when they
were invented by Thomas Edison, and have changed little since. They work
by passing the electrical current through a thin filament which
presents a high amount of resistance, creating heat. In fact that is
what makes it work, as it creates a large amount of heat and as the
filament gets hot enough, (almost instantly), it glows bright enough to
emit light. The properties of the filament allow it to stay intact,
even as it nears the point of melting. The also creates a few
disadvantages. One of the disadvantages is that most of the energy, as
much as 98% is wasted and lost as heat, the very effect that makes it
work. Another is the stress of so much heat, near melting for the
filament, make for a short life, as eventually the filament does fail.
There are a few variations of the incandescent bulb using different
materials for a filament to obtain different intensities or colors of
light, but all work on the same principals, high heat.
Halogen
Light Bulbs- Halogen light bulbs are similar to incandescent bulbs.
They use a gas around the filament. They are smaller bulbs than
incandescent and produce more heat. Whatever you use them for needs to
be rated to handle the extra heat.
Compact Fluorescent Lights
(CFLs) - Compact fluorescent lights are glass tubes, which can be
straight or more commonly bent and curled into a small twisted ice cream
shape. At both ends of the tube are electrical contacts to pass
electrical current through an inert gas and exciting the electronics so
that they travel through the tubes which are coated with a trace amount
of mercury and a coating of a phosphorus material. As the excited
electrons move they strike and transfer their energy to the phosphor
causing it to glow and emit light. Combinations of different phosphors
and invert gases can produce different colors and effects.
The
benefits are: they use a fraction of the power that incandescent light
bulbs use and generate very little heat. They also have a longer life
than incandescent.
The down sides are that they contain mercury and
present challenges with safe disposal, and many people do not care for
the seemingly harsh light they produce, which is not as “soft” to the
eye as incandescent bulbs, and they don’t work well with dimmer
switches. The good news is technology is advancing and they are finding
ways to make the light easier on the eyes.
Light Emitting Diodes
(LEDs) - LED lights were discovered in 1962 almost 50 years ago, and
only as of the last decade becoming very popular for many lighting,
besides simple indication lights and computer displays.
They are
literally a tiny silicon transistor, nearly the size of a human hair.
By passing a tiny amount of current thought a silicon gate laced with
phosphorous molecules, the current greatly excites the phosphor causing
it to glow very brightly. It took years for scientists to find the right
phosphorous elements to create different colors of light. Believe it or
not, white LED’s were very hard to make and did not come to be made
until years after first discovery of the LED. Red and green were first,
followed shortly by yellow and about 30 years later blue and white.
Advantages
are huge. Being very tiny, they can be used anywhere and when
clustered into shapes can create endless effects used for thousands of
purposes. Other than size, 2 other major advantages are: extremely low
power use, and very very long life. Until relatively recently, LED
lighting in scale to be used for more than simple indicators or
displays, was very expensive, but as the technology continues to grow.
Costs are dropping.
Disadvantages are few and gradually being
overcome, being small and their nature, they do not produce a very good
long range beam more than a few feet, as would be needed for car
headlights. Also, lots of the little LEDs have to be clustered together
to produce enough useful light to illuminate an area, making them more
expensive for large scale use. Like CFL’s the color tone and light is
not quite pleasing to the eye. But both of those problems will be
solved very soon.
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