Light Bulb Types

Before the invention of the light bulb, it was quite a grueling task to illuminate houses and buildings. Candles and oil lamps were earlier used for this purpose, but these light sources used to leave residues like, soot in the surrounding areas, which was quite annoying. We all know who invented the light bulb. It was the American scientist Thomas Alva Edison, who gave the world an efficient and convenient way for lighting in the year 1879, by inventing the light bulb. The light bulb invented by the famous scientist Thomas Edison was an incandescent bulb. Over the years, many different bulbs have been developed.

Types of Light Bulbs

There are many different types of light bulbs, which have been developed by keeping some particular uses and applications in mind. Out of these, the most important ones are, incandescent bulbs, halogen bulbs, fluorescent bulbs, compact fluorescent lamps, high intensity discharge (HID) lamps, low pressure sodium lamps and light emitting diodes (LED).

Incandescent Bulbs
Incandescent bulbs are one of the popular and inexpensive bulbs. This type of bulb contains a tungsten filament. Electricity is used to heat this tungsten filament, as a result of which the light bulb glows. Incandescent bulbs are known to give warm and steady light, and is largely preferred for household applications or home lighting. The tungsten filament inside the bulb is placed either in a mixture of nitrogen or argon gas, or in vacuum.

As far as efficiency is concerned, incandescent bulbs are not very efficient, as much of the heat consumed is given off as heat. These bulbs also burn out quite frequently. This is because, when the filament is heated, tungsten evaporates from it and deposits on the sides of the bulb, which causes the filament to become thinner. But the filament thins out unevenly, for which the thinner areas heat up faster and then break off easily. The most common types of incandescent light bulbs are, reflector bulbs, A-line, globe, candle, tubular and flicker bulbs.

Fluorescent Bulbs
Fluorescent bulbs are more energy efficient than incandescent bulbs, as they produce more light per watt. The fluorescent bulbs or tubes are filled with argon gas and mercury. When electric current is passed through the tubes, ultraviolet radiation is produced, which then bombards the phosphorus coating. This in turn, produces the light. Traditionally, fluorescent bulbs used to come only in cool white color. But, nowadays they can be found in many different colors. Fluorescent light bulbs are ideal for office and kitchen lighting, where you have to light up a large area. The different types of fluorescent light bulb include, T-16, T-5, T-8, T-12, U-tube, circle tube, linear bulbs and aquarium bulbs.

Halogen Bulbs
Halogen bulbs are similar to the incandescent bulbs. They also contain a tungsten filament through which electricity is passed to produce light. The only difference is that the halogen bulbs contain halogen gas, i.e. the tungsten filament is placed in a tube filled with halogen gas. Compared to incandescent bulbs, halogen bulbs are more energy efficient, as they consume less energy to produce the same amount of light. They also last more than incandescent bulbs, as the halogen gas causes a chemical reaction, which removes the tungsten from the sides of the bulbs and deposits it onto the filament. Halogen bulbs are preferred for the brilliant white light that they emit. There are mainly two types of halogen bulbs. These halogen light bulb are, low voltage and mains voltage.

Compact Fluorescent Lamps (CFL)
Compact fluorescent lamps are similar to fluorescent bulbs, as both the types of bulbs work in a similar fashion. Compact fluorescent lamps or CFL are one of the most energy efficient bulbs with longer life span. Compared to incandescent bulbs, compact fluorescent bulbs use about 67% less energy. So, they are the energy efficient light bulbs for the home. However, they are more expensive than incandescent bulbs, and they contain a small amount of mercury, for which care needs to be taken while disposing them.

High-Intensity Discharge Lamps
High intensity discharge lamp is a type of electrical lamp, where light is produced by striking an electrical arc across the tungsten electrodes, placed inside a specially designed inner glass tube. The tube is filled with gas and metal salts. Most of the high intensity discharge lamps contain auxiliary equipment such as, ballasts and starters to facilitate the operation of the bulbs. The only exception is the self-ballasted mercury lamps. Other examples of high intensity discharge lamps are metal halide and high pressure sodium. These bulbs are prized for energy efficiency, long life and also for the high levels of light that they produce.

Low-Pressure Sodium Lamps
Low pressure sodium lamps are known to have the highest level of energy efficiency, among all the available lighting devices. They produce a yellow light and so, low pressure sodium bulbs are not preferred, if color rendition is a priority. These bulbs need some time to reach full brightness. This warm up time period is however, quite brief. As far as the working mechanism is concerned, low pressure sodium lamps are similar to fluorescent lamps. They also need a ballast and they are usually preferred for outdoor lighting, lighting streets, pathway and parking lots.

Light Emitting Diodes (LED)
These are the light bulbs that do not contain a filament. They are known for their long life span, as well as low consumption of power or energy. They are primarily used as indicator lamps in certain devices, and they can be found in traffic signals. LED lights are used for aviation and automotive lighting as well.