A useful guide article about how to choose suitable lamps
2008-08-22

                                                                                    A useful guide article about how to choose suitable lamps       Since the first electric bulb was invented in 1879 by Thomas Alva Edison, The light bulb, in particular, profoundly changed human existence by illuminating the night and making it hospitable to a wide range of human activity.                                                                                                            And now lamps already become one necessary part of human beings’ lives.       For most applications, lamps can be divided into four categories: Incandescent       Incandescent lamps are the most familiar source of light and are widely used in residential and other low-annual-hours-use applications. The popularity of the incandescent lamp is due to the simplicity with which it can be used and the low price of both the lamp and the fixture. Also, the lamp requires no special equipment, like a ballast, to modify the characteristics of its power supply. In can descents are often used in commercial and industrial applications where the intended hours of use are low (less than 500 hours per year), where needed for aesthetic purposes, or where initial cost is an overriding criterion. Every product both has its advantages and shortcomings, Incandescent lamps are no exception. Strengths:    Low initial cost    Excellent color rendition    Instant starting    Inexpensive dimming capability    Skin-flattering warm color    Small size, which allows it to be, used in point fixtures, such as spot lamps    Wide variety of shapes, sizes, colors and wattages are available    Output unaffected by high or low ambient temperatures    Simple to operate and install    Requires no ballast    High brightness light source    Available in many colors    Variety of filament design possibilities offer optical control, accurate distribution patterns and critical service operation Weaknesses:    It has relatively short useful life with poor over-voltage tolerance. At 10% over voltage, life is reduced about 75%!    It is a very inefficient source of light. On average, less than 10% of the wattage goes to produce light; the remainder becomes heat.    High heat component can create hidden energy costs due to increased cooling needs.                                                                                              Fluorescent       Fluorescent lamps are the second most common light source. They are the most common source used in commercial buildings, producing about two-thirds of our nation's illumination.       Fluorescents are easily distinguished by their tubular design. They come in circular, straight or bent in a "U" shapes.       Fluorescents are a good retrofit for incandescent lamps that operate a significant number of hours. Circular fluorescent lamps can be used where exposed socket incandescent bulbs are currently used. Compact or PL fluorescent lamps (available in 5-40 watts) can be substituted for many incandescent bulbs and will fit in many types of fixtures.       Facilities already using fluorescent lamps should consider high efficiency fluorescent lamp designs. They produce about the same amount of light, while saving about 10 to 15% of the energy usage. Strengths:    It is 4 to 5 times more efficient than incandescent, and an exceptionally long life (10 to 20 times greater than incandescent).    It is easy to maintain.    Lamp life is greatly affected by the average number of hours the lamp is cycled on and off.    The lamps are also low cost and available in a wide range of sizes and colors.    Relatively low surface brightness and heat generation, and are relatively insensitive to small changes in building voltage. This can be very important where brownouts are common. Weaknesses:    Most lamps are relatively large and require a relatively expensive fixture.    The ballasts in fluorescent fixtures can have an objectionable hum (some louder than others).    Ballasts are now given a noise rating. Quiet ballasts are recommended for office areas, louder and less expensive ballasts can be used in industrial facilities.    Fluorescent lamps are temperature sensitive and may have difficulty starting at low temperatures. Also, lumen output drops at low and high temperatures. Special ballasts are available for low and high temperature applications.    While dimming of fluorescents is possible, it requires special, relatively expensive ballasts.                                                                               High Intensity Discharge        High Intensity Discharge or "HID" is the term commonly used to designate four distinct types of lamps that actually have very little in common. They are high pressure sodium, low pressure sodium, metal halide, and mercury vapor.                                                                                              Light Emitting Diode (LED)       Light Emitting Diode (LED) Lamps represent new technology with expanding applications, particularly in color and specialty applications. If you still think LEDs are only for little red indicator lights on electronic gizmos, check out LEDs. LED replacements for incandescent bulbs are available for numerous applications in many sizes, shapes, colors and packages and so on.       As one of the most advanced technology product, LEDs have much more advantages:    LEDs produce more light per watt than incandescent bulbs; this is useful in battery powered or energy-saving devices.    LEDs can emit light of an intended color without the use of color filters that traditional lighting methods require. This is more efficient and can lower initial costs.    The solid package of the LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner.    LEDs can very easily be dimmed either by Pulse-width modulation or lowering the forward current.    LEDs light up very quickly. A typical red indicator LED will achieve full brightness in microseconds. LEDs used in communications devices can have even faster response times.    LEDs can have a relatively long useful life.    LEDs, being solid state components, are difficult to damage with external shock, unlike fluorescent and incandescent bulbs which are fragile.    LEDs can be very small and are easily populated onto printed circuit boards.    LEDs do not contain mercury, unlike compact fluorescent lamps.                                                                            After the detail introductions of different lamps above, I firmly believe you must have had being very familiar with the lamps, and if you need to buy lamps, and you will have enough confidence to buy a suitable lamp for yourself.