All About Bulbs
Incandescent, Fluorescents, and Halogen are the three most typically used types of light bulbs. They are used in everything from your bedside table lamp, recessed lighting fixtures, to your favorite restaurant’s sign.
The incandescent light bulb has been around since the 1860’s, when Sir Joseph Wilson Swan produced the first light bulb with carbonized paper as a filament. Thomas Edison exhibited his incandescent light bulb for the first time in 1879. Since then, the incandescent light bulb has changed greatly. Now, instead of carbonized paper, an incandescent bulb uses Tungsten as a filament. In order for an incandescent light bulb to work, the inside of the bulb must be devoid of any air. Then when electricity is applied to the bulb the filament heats up and glows, producing light.
There are two down sides to incandescent light bulbs. First 90% of the electricity used to produce light is turned into heat, and only 10% of the electricity is turned into light. Thus, they are not very energy efficient. Second is the short life span of the bulb. Due to the constant heating of the filament, the tungsten starts to evaporate. This causes the filament to become weaker and eventually break. The color of light that an incandescent bulb produces is not a white light. It produces light with an orange or yellow tint to it.
A few examples of typical applications where incandescent light bulbs are used are in table lamps, hall light fixtures, bathroom light fixtures, chandeliers, and ceiling fan lights.
The halogen bulb is an improved incandescent bulb. The gas inside the bulb has some traces of halogen. Halogen causes a chemical reaction inside the bulb, and helps to return the evaporated tungsten back to the filament. In order for this chemical reaction to take place, the bulb must burn at hotter temperatures, on average 250 degrees Celsius. Due to the higher temperature, and the bulbs small size, the bulb is comprised of a strong, heat-resistant glass. This allows the manufacturer to use a better quality fill gas inside the bulb. The advantages to this for the consumer are twofold: the filament will last longer, thus the life expectancy is longer, and the percentage of electricity turned into light is higher than a standard incandescent light bulb.
The halogen bulb is mainly produced in two different styles. The first has a screw-in type base, the same as your standard incandescent light bulb. In this type of halogen bulb there is an outer shell that prevents you from touching the actual bulb. A couple of applications of the bulb would be in recessed can lights and outdoor flood light fixtures.
The second style has two stems at the base of the bulb which stab into the light fixtures socket. With this style you can not directly touch the bulb with your bare hands for the oil from your skin will boil on the bulb and cause it to burn out very quickly. If the bulb gets touched it can be wiped down with some alcohol based liquid.
Due to the bulbs small size, it is ideal for certain task light fixtures. Some of these would include: under cabinet fixtures, small desk lights were space is an issue but a lot of light is needed, certain types of recessed fixtures, light fixtures used to light artwork, and some outdoor yard light fixtures.
There is a new version of the halogen bulb called the Halogena. This bulb still uses the same basic principles as the halogen bulb, but is designed to be used in a lot of the same applications as the incandescent light bulb. The Halogen and Halogena bulbs produce light that is of a truer natural white light and does not change the color of objects the way an incandescent bulb will, which makes it desirable in lighting various works of art.
The fluorescent light fixture has probably the most diverse uses of any light fixture. It is used in everything from under cabinet light fixtures, make up mirrors, office, warehouse, and shop lighting, to sign lighting,
department store lighting, and your parents’ main kitchen light. It also comes in varying lengths and shapes. From 12 inches to 96 inches long, and from a straight line to a circle, to a U shape, to a spiral that will work in your table lamp.
The fluorescent bulb–perhaps one of the most complicated bulbs the average consumer uses–is comprised of several parts. First are the pins at each end of the bulb which lead to the electrodes. Unlike an incandescent bulb, where the filament is run either the length or width of the bulb, the electrodes do not run the length of bulb. They are just barely inside the bulb at each end. Then the bulb is usually filled with ARGON gas and is kept at a very low pressure. The inside of the glass is covered with a phosphor coating. With Mercury being last but not least, it is inside the bulb as well.
That was just the bulb; you also need a Ballast to make the bulb light up. The ballast takes the incoming electricity (voltage) and increases it. When the increased voltage is sent along the electrodes, it causes electrons to migrate from one end of the bulb to the other. The mercury is changed into a gas, and when the electrons and gaseous mercury collide, the electrons are raised to a higher energy level. When the electrons return to their original energy level, they produce (or release) light photons. Now these light photons are of the Ultraviolet wavelength which the human eye cannot see. This is where the phosphors coating comes into play. As the light photons hit the phosphor coating, the atoms in the phosphor become excited. When the phosphor atoms return to normal they produce light that we can see. All of this takes place with more of the electricity being turned into light and less into heat. So fluorescent light bulbs burn cooler and use less electri city to produce the same amount of light as an incandescent or a halogen bulb and generally last 6 times longer.
Fluorescent bulbs, however, do not produce a natural white light like that of a halogen and are known for changing the way color appears on anything. Manufacturers are able to change the light quality of the bulb by changing the phosphors coating inside the bulb. The more common bulbs are the Warm White, which produces about the same color quality an incandescent bulb, and Cool White which produces a bit more white light. There are also the Full Spectrum and Daylight bulbs that would be used for specific type lighting requirements. Talk with your local light bulb specialty retailer or electrician to see which one would be right for you.