Different Types of Fluorescent Light Bulbs

Basics about Fluorescent Light Bulbs

Most fluorescent light bulbs process energy in the same way to produce light. The differences between the bulbs come in the color and brightness they emit, the projected length of time the bulb will function and the diameter and length of the bulb.

Colors

The color of a fluorescent light bulb comes from a powdery coating of mixed phosphors inside the tube. The mixture of phosphors determines the color given off by the light bulb. Fluorescent light bulbs come in many colors of white:

• Daylight – This bulb casts a blue tone.
• Cool white – This is the most commonly used in commercial settings. It has a slightly bluish color. It is not recommended for residential use because it has a distortion that makes colors look washed out.
• Warm white – This bulb is recommended for residential use. It has a slightly pinkish color.
• Full spectrum – This bulb shows the truest color and is brighter than the cool white or warm white bulbs.

Brightness

A brand new fluorescent light bulb takes a few hours to achieve maximum brightness. The bulb's brightness will start to decline from that point on. The common 48-inch, 4-watt cool white fluorescent tube starts with a brightness of 3,250 lumens, the measurement for the brightness of light. Within six hours, the brightness of the bulb will have declined to an average of 2,960 lumens.

Life

The life of a fluorescent is based on how often the bulb is turned on and off, not just how long it is on. The lamp life projections shown on the bulb's package are based on operating the lamp for three hours each time it is turned on.

Construction

The construction of a fluorescent lamp or bulb is generally the same from lamp-to-lamp and from bulb-to-bulb. This means that you don't have to worry about the mechanism of the lamp or bulb when you are looking for a replacement – you can just concentrate on the length and the diameter.

• Lamp ballast – The ballast is the part of the fluorescent lamp that limits the amount of electrical current flow. It can be magnetic or electronic. The size of the ballast determines the size of light bulb that is needed. The ballast can be changed to accept a smaller diameter, more energy-efficient bulb.
• Lamp starter – The fluorescent bulb usually has an automatic starter that kicks on when you turn on the light. Smaller lamps such as camping lanterns often have a push button starter.
• Bulb pin connector – Most long tube light bulbs have two pins at each end. These are called "bi-pin." The pins come in various sizes, but the most common in homes is the medium bi-pin. Miniature bi-pin sockets usually have a push button starter. They are used in small lamps such as lanterns and car lights.

Different Types of Fluorescent Light Bulbs

The traditional fluorescent light bulb has always been a 24-inch, 36-inch or 48-inch 1 ½-inch diameter tube with two pins on each end. Today, there is a wide variety of different types of fluorescent light bulbs -- in a variety of lengths and diameters.

The diameter of the tube is described in eighths of an inch. There are twelve eighths in 1 ½ inches, so a T-12 fluorescent lamp is 1 ½ inches in diameter.

The fluorescent light bulbs on the market include:

• T-16 – This tube has a 2-inch diameter. It is a preheat lamp, so it requires a starter. The tubes are usually 60 inches long.
• T-12 – This tube has a diameter of 1½ inches. This is the most common diameter of tube-shaped light bulbs. It is usually bi-pin and it does not require a starter. It is available in a variety of lengths including a 15-inch (14-watt), an 18-inch (15-watt), a 24-inch (20-watt bulb) as well as a 36-inch and a 48-inch bulb.
• T-8 – This tube is in the process of replacing the T-12. It has a 1-inch diameter, it is more energy-efficient and it gives off more light than the T-12. It is available in a variety of lengths including a 12-inch (13-watt), a 15-inch (14-watt) and an 18-inch (15-watt).
• T-5 – This tube is more efficient than the T-8 and is currently used in some commercial locations and throughout Europe.
• U-tube – This is a tube bent in half to form a "U" shape. A 48-inch bulb bent into a 24-inch U-tube bulb is brighter than a 24-inch tube bulb.
• Circle tube – This tube is either 8 inches or 12 inches in diameter and will have a 4-pin connector.
• Miniature bi-pin sockets – The bulbs to fit these sockets are 5/8-inch in diameter. They are usually 6, 9, 12 or 21 inches long with wattages of 4, 6, 8 or 13 watts respectively.
• Compact fluorescent light (CFL) – This is a tube that has been reduced to the size of a pencil and then folded or twisted into the shape of a light bulb. It has a screw socket so it can easily screw into a lamp socket. It is more energy-efficient than an incandescent bulb, but not any more energy-efficient than a tubular fluorescent lamp. Compact fluorescent bulbs have a more pleasing color than a tube-shaped fluorescent bulb. Some have electronic ballasts.
  • Screw-in bulbs – This is the most popular energy-saving light bulb. They can fit almost any table lamp or light fixture. They cannot be dimmed.
  • NEOLITE™ low-mercury – This is one of the smallest CFLs available, so it fits most lamp sockets. The bulb is ENERGY STAR qualified and contains only one milligram of mercury, less than half the mercury of other brands. It also contains led-free solder and glass. It is a bright bulb (70 lumens per watt), has excellent color and a 10,000-hour rated life.
  • Flood lights – These flood lights use only about 25% of the energy used by regular incandescent flood lights. They also produce less heat. They can be used in recessed can fixtures and track lighting. They cannot be dimmed.
  • Dimmable lights – These bulbs offer energy savings and they can be dimmed to 20% of their full light output.
  • Decorative torpedo bulbs – These decorative light bulbs are an energy-saving alternative to incandescent decorative bulbs for chandeliers and light fixtures.
  • Colored light bulbs – These bulbs are often used in restaurants, bars, nightclubs or in homes – wherever you want a festive mood. They are available in red, green, blue, yellow and pink. They have a long life.
  • GE 2D bulbs – This pretzel-shaped General Electric bulb has been around since the early 1990s. They are commonly used in torchiere lamp fixtures and table lamps.
  • 3-way bulbs – The compact fluorescent 3-way bulb saves energy and lasts much longer than incandescent 3-way bulbs. They can be used in any lamp with a three-way switch. They cannot be used in touch lamps.
  • GU24 Twist and Lock bulbs – These are a new generation of compact fluorescent bulbs that allow you to change the wattage of the bulb without changing the fixture. The bulb can be used in the Line Voltage Socket (LVS) that is commonly used on today's modern Energy Star light fixtures.