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02/22/11 |
High Power HID Spotlights Making Halogen Obsolete
The standard spotlight is a fairly basic modification of the ever reliable but soon to be extinct incandescent light bulb. Two key differences, however, set the dedicated spotlight apart from the general illumination lamp. First and foremost, spotlights are intended to illuminate objects at extended distances. To that end, spotlights generally make use of higher powered luminaries than general purpose lighting, with halogen lamps being the predominant type. Halogen bulbs although operating on the same principals as regular incandescent bulbs, are preferred over garden variety incandescent bulbs for spotlight use because of their ability to produce more light output with the same amount of power, while lasting somewhat longer than a regular bulb before requiring replacement.
The other significant difference between spotlights and general purpose lighting is found in the reflector assembly. Almost every type of lighting fixture in existence contains a lamp and a reflector. Even the shade on your table lamp is at its most basic a type of reflector-diffuser. The important factor here with reflectors is the light’s intended purpose. General area lights are required to illuminate a large area in all directions without producing glare and so make use of reflectors and diffusers that spread light evenly over a wide area and soften the light. Spotlights, on the other hand, require the light to be tightly focused and directed in a specific direction and so are designed to concentrate and focus light rather than spread and diffuse it. The biggest factor then in how well a spotlight “throws” a beam, or how far it can reach and how well focused the beam will be, is the reflector assembly.
Typical incandescent lamps are notoriously inefficient light sources. Up to 90% of the electrical energy consumed by an incandescent bulb is wasted as heat, with only 10% radiated as light energy. Halogen bulbs improve on this ratio through the use of specially designed filaments and specific gases that increase the output and longevity of the wire filament used in the incandescent bulb. The improvement though is slight and the quality of the light produced is somewhat low grade as it tends to be yellowish and of low intensity. A good reflector assembly further improves the intensity by concentrating and focusing the light energy, but has no impact on the quality of the light produced. Cheaper general use and mid grade spotlights like those commonly found in the household closet or out in the shed tend to be halogen units. They are usually effective for general use, but are not the best choice for serious applications such as military, law enforcement or security. Non professional applications like hunting and boating can also require a greater degree of power and efficiency than the typical halogen spotlight is capable of providing. Overall, the common halogen spotlight generally has moderate power and a fairly short throw limiting its effectiveness.
Today’s truly effective spotlights make use of advanced materials and designs to produce intense and highly focused illumination that the typical halogen spotlight simply cannot match. Of the alternatives to the incandescent lamp, the high intensity discharge or “HID” lamp is currently the most powerful luminary available. These lamps produce light differently than the incandescent halogen. Rather than relying on a filament strung between two contact points, HID lamps have a gas and metallic salts filled chamber which surrounds two electrodes. When power is applied to these electrodes, an electrical arc is produced that ionizes the gases and salts, resulting in glowing plasma that creates light. Depending upon the types of gases and salts used, these HID lights tend to produce intense light that is usually skewed towards the bluish and white end of the light spectrum. The best HID spotlights usually use mercury vapor gas and metal halide salts to produce intense white light with little of the bluish tint sometimes associated with HID.
With an efficiency of 100 lumens per watt or more, HID lamps far surpass incandescent lamps for sheer power. Incredible results are obtained, however, when these HID lamps are paired with an effective reflector assembly. There are 35 watt HID spotlights like the Rechargeable HID Handheld Light from Magnalight.com that can throw a light beam for three quarters of a mile or more. This kind of performance is made all the more remarkable by the fact that HID lamps actually use less power than would be needed for an incandescent lamp to produce the same results. An added benefit of the HID lamp is that since there is no filament, the lamp is much more durable and resistant to damage from shocks and vibrations while lamp longevity is increased up to ten times that of an incandescent. For applications like those found in the military or law enforcement, this power combined with high durability for all intents makes the halogen lamp nearly obsolete for everything but the most basic of duties.
While the HID lamp provides the basic raw power, reflector design is critical to getting the power focused and applied. In a cheap flashlight for example, it’s easy to notice how much of the light is actually applied to the main part of the light beam and how much is lost to light spillage and spread. Generally speaking, with a cheap flashlight you’ll note that aside from brightest center point of the light beam, there is a great deal of area outside this beam peripherally illuminated. This is what’s considered spillage and spread and it represents a great deal of lamp power being wasted. Additionally, many cheap lights will show dark spots and irregularities in the shape of the light beam itself, which directly represents both a poorly formed reflector and a poorly designed bulb. Irregularities in the shape of the light beam are caused by irregularities in the shape of the reflector, while dark spots represent the physical aspects of the bulb interfering with the smooth spread of the light produced. Both represent poor efficiency and wasted light power. Overall, a good spotlight will exhibit little spillage and spread and the beam will be well focused with few dark spots and irregularities if any in the shape of the light beam. This is one of the easiest ways to determine if a spotlight has been designed and built well. If the beam is sloppy, then it’s likely that so too is the lamp construction and design.
If you’ve ever seen a flashlight or spotlight in use and wondered how they got such an intense and powerful light from such a small package, chances are that what you saw was a quality HID spotlight in action. More and more, these HID lights are seeing use in all of the professional services and this popularity is fast spilling over into the public sector as well as boaters and outdoor enthusiasts realize the benefits of increased power and safety these lights offer. The next time you’re in the market for a portable light, take the time to look at some the HID offerings on the market today. You’ll be glad you did. |