A LED flashlight produces light through light emitting diodes (LEDs) rather than an incandescent bulb, making them cooler, more energy efficient and tougher.

The incandescent light used in traditional flashlights utilizes a filament wire encased in a glass vacuum tube or bulb. When electricity is supplied to the wire from the batteries, the wire glows with heat that produces light. The heat, however, is not only lost energy but it eventually burns out the wire and the bulb must be replaced.

A LED flashlight harnesses light created by an entirely different process. Two types of semiconductor materials are used in a LED: one type that has an abundance of free electrons and the other that has a deficit. When enough energy is supplied in the form of electricity, a threshold is reached that pushes some of the free electrons in the abundant material to jump to the attracting material. When that electron takes its place in the new material a photon or particle of light is released.

The color of the released light is dependent on what kinds of materials are used and how much energy is required for the electrons to make the jump. If a low amount of energy is required the light emitted will be in the infrared or red wavelength. If a comparatively high threshold much is reached, the light emitted will be up in the blue/white wavelength.

OLED or organic light emitting diode is a newer technology that uses carbon-based materials rather than synthetic materials. OLED is well suited for display screens and will likely replace LCD technology, but OLED flashlights may or may not come to pass.

LED flashlights to come in many different sizes and candle powers as do regular flashlights. The number of LEDs in the flashlight will determine its brightness. LEDs are coated with a clear solid resin, making them nearly indestructible. If you drop a LED flashlight the chances are slim that any damage will occur. Many LED flashlights are also waterproof.

A LED flashlight draws only 5-10% of the power of an equivalent light bulb, conserving batteries and saving money. It can also hold up under 5-10 years of continual use!

The light from a LED flashlight is pure, bright and true and can be seen for up to 1 mile (1.6 kilometers). Unlike incandescent bulbs that produced rings of brighter light within the scope of the beam, LED beams are evenly illuminated, like a fluorescent light.

One type of LED flashlight does not even require batteries. Based on the Faraday Principle of Electromagnetic Energy, a copper wire is encased in a magnetic field inside the flashlight. By shaking it vigorously for 15-30 seconds, enough electricity is generated to produce light for about 5 minutes. If you need light beyond that period, you simply shake the flashlight again. This product has no replaceable parts and is a great emergency light.

A LED flashlight might cost a little more than a traditional flashlight, but the money saved in batteries and bulbs will offset that cost. It is nearly indestructible under normal use, is more environmentally friendly, can be waterproof, and emits purer truer light. With all of these advantages, it's clear that LED technology is lighting our way to a brighter future.

One application where LEDs (light emitting diodes) shine is in flashlights. Because LEDs have high brightness, low power consumption, long life, small size and other characteristics, they're ideal for portable lighting. You can choose a good LED flashlight if you look for some key features.

1. Decide why you want the flashlight. 

Will you use it for camping? Will you carry it in your car? Will you leave it at home in case of a power failure? Do you need something particularly large or small? Do you need it portable? Will you carry the light or do you want it to be able to strap on or mount to a stand?

2. Set a Budget

Many flashlights are available for under $10 or $20, but these are often cheaply built, and will not last as long as one that costs more than $25. Most of the very popular high-end flashlights today are priced around $50.

3. Look for the brightness, measured in lumens. 

How far do you need to be able to see?

 

4.Check the number of LEDs. 

The number of LED's is usually less important than the brightness, but it's often listed. Any flashlight that's worth the money, will feature only one LED. Most cheaper lights that have multiple LED's are not very bright, and often do not offer a strong, focused beam.

5.Choose something with good soldering, connections, and switches. 

Most LEDs are very reliable, so it's often the surrounding construction that will fail first if it's not well constructed.

6.Choose a battery type that's right for you. 

The types of flashlights sold at most major retailers are very limited and are usually geared toward standard disposable batteries. Rechargeable Nickel Metal Hydride (NiMH) batteries are a better choice. Most retailers sell these. For these types of batteries to work in a LED flashlight, the light must be an AA flashlight. A flashlight made for lithium batteries cannot use standard AA or NiMH batteries. The best lithium battery flashlights are usually only available at online retailers. Disposable lithium batteries are expensive and don't last long in high-power flashlights. Rechargeable lithium batteries are much cheaper to operate. They are also only available through mail order.

Conventional alkaline batteries have a long shelf life but must be replaced. Alkaline batteries are also prone to leaking if left stored for long periods.

Lithium-ion batteries can be recharged with a lithium battery charger. Rechargeable lithium batteries have an extremely long shelf-life, and once charged, will hold their charge up to one year without much loss. Disposable lithium batteries, known as CR123's, can be stored up to TEN years with no possibility of leakage or degradation.

Even a rechargeable battery may someday need to be replaced. Most rechargeable batteries whether they are lithium or NiMH can usually be charged up to 500 times before they'll no longer hold a charge.

7.Choose an appropriate size and weight. 

LED flashlights are available in a range of sizes and weights, ranging from tiny coin cell key chains to large, stand-mounted work lights.

8. Look at the led. 

With them off, you can look at the consistency of the work that went into mounting them.

9. Turn the light on and look at the shape of the spot it projects. 

Look for an even, round light, rather than an uneven distribution of light. LED flashlights generally do not have an adjustable focal length, so it's important to choose one that's right, to begin with.

10. Choose a housing material. 

Plastic is lightweight, cheap, and will not stand the test of time; aluminum is likely to be more durable. Most of the popular lights today use aircraft grade aluminum.