The Different Types of Flashlight Bulbs|
Article- July 2012 By LXFlashlights.com
Explosion Proof HID Flashlight
Incandescent flashlight bulbs have been the dominant type used in portable handheld lighting devices for decades. They are simple in design and operation and are very cheap to produce. The low cost and simplicity of the incandescent light bulb works well with the simplistic design of a basic flashlight, allowing manufacturers to produce affordable and portable lighting in mass quantities quickly. Despite the low cost and simplistic nature of the common flashlight, the value of the common flashlight is quite low due in large part to its incandescent bulb. Although cheap to produce, the incandescent bulb is fragile and very inefficient. The average flashlight has an incandescent bulb with a lifespan rarely surpassing 50 hours, and its poor efficiency results in very short battery life. Although a basic flashlight may be cheap to purchase initially, the cost of replacing batteries and bulbs can quickly surpass the cost of the flashlight itself and make long term use rather expensive.
Incandescent bulbs are little more than a glass globe surrounding a wire filament strung between to contacts. The glass globe normally contains a vacuum to increase the life of the filament, and may sometimes contain gases such as xenon or halogen to help improve efficiency and further increase filament life. The wire filament produce light through the process of electrical resistance. When current is fed to the two contact, the resistance of the wire filament causes it to heat up, in turn releasing energy in the form of heat and photons, or light. The vacuum of the bulb helps to prevent the filament from burning, and added gases as noted above can work to further reduce filament degradation and increase the amount of current fed into the wire, thus allowing the bulb to burn brighter. Despite the use of a vacuum or gases, the filament in the bulb still slowly degrades and wears away, eventually leading to failure of the bulb. Although simple in design, the incandescent bulb is highly inefficient, with much of the energy fed into it wasted as radiated heat rather than light. It is also quite fragile, making it easy to break should the bulb be subjected to significant impacts or vibrations.
LED Light Emitters:
LED light emitters are a much more advanced form of luminary and produce light in a manner wholly different from the incandescent bulb. Rather than heating a filament, and LED works by feeding electrical current through a small piece of semi-conducting material. As the current passes through this material electrons are split and emerge in part as photons. This process is called electroluminescence and it is far more efficient way to produce light compared to the resistance of a wire filament. The advanced design of the LED give it several distinct advantages when utilized in flashlights. An LED flashlight will produce more light using less battery power, with the result being a much longer run time on a single set of batteries. Whereas a typical flashlight with incandescent bulb might run for 2 hours on a single set of batteries, an LED flashlight can run for several hours. In some cases, particularly in lower output LED flashlights, a set of batteries can last in excess of 50 hours.
The design of LEDs is such that they are much more durable than incandescent bulbs as well. LEDs do not require a vacuum or specialized gases to operate, thus they do not require a glass bulb. Furthermore, there is no thin wire filament, and the heat produced is much lower. An LED is comprised of semi-conducting material sandwiched between layers of supporting materials and phosphor or other coatings designed to modify the color of the light emitted. The LED itself is usually protected by a covering of hardened clear acrylics or epoxies, all of which results in a very rugged assembly. LED lamps give these flashlights a huge advantage in durability and longevity over their incandescent counterparts, making them more cost effective in the long run.
High Intensity Discharge bulbs, or “HID” for short, are the most powerful of all the flashlight lamps and are capable of producing intense output. This high power capability makes HID flashlights a favorite among those requiring a flashlight for tactical or professional applications such as those found in the military, law enforcement and security fields. Like the incandescent, the HID bulb requires a glass globe, but rather than use a vacuum or filament, the HID bulb has only two contacts and is filled with XENON gases and metal halide salts. When a high power current is applied to the contacts, an intense and hot arc is created within the bulb, which in turn ignites the gases and salts, creating a plasma which gives off light. This light is very intense, and very hot, however, this light producing process is also much more efficient than that in the incandescent. The HID bulb is more durable than the incandescent bulb since it does not have a wire filament, but since it does have a glass bulb, is still susceptible to shattering if dropped. The high heat created by an HID bulb can also make the flashlight difficult to handle, and it is very easy for accidental burns to occur if the user is not very careful.
HID flashlights require some additional hardware to be built into the flashlight body in order for the unit to operate. HID bulbs require an initial very high electrical current to create the arc which ignites the internal gases. Once ignited, very little current is need to maintain ignition and keep the lamp burning. To achieve the high current needed to start the lamp, then lower it to a normal operating level, and electronic ballast is used. This is usually incorporated into the flashlight body and is a fairly rugged assembly in its own right, so durability of the light is not compromised by the addition of the required ballast. However, the ballast does add weight and expense, making HID flashlights significantly heavier and more expensive to operate and purchase.
For general around the house use, and incandescent bulb flashlight is usually adequate, although for a little bit more money upgrading to an LED flashlight will yield a much better value for your investment as well as an all around much better performing flashlight. For maximum power output it is hard to beat an HID flashlight. HID flashlights are ideal for tactical use as well as industrial applications, but it should be kept in mind that all that power comes at a higher price.