A flashlight is a small but powerful lighting device that is generally used to provide illumination in relatively dark areas. These devices are useful for skilled workers such as carpenters, masons, plumbers, and other building contractors who may have to work onsite in less lighted areas. Since Flashlights are battery operated, they also come in handy when there is a power failure and are useful devices to keep at home. Mini flashlights can fit into pockets and glove boxes and can be used when servicing computers and other electronic devices.

Features and working of a flashlight

The lighting component of a flashbulb is an incandescent light bulb with a parabolic reflector. The light bulb consists of a thin filament that lights up when subjected to the passage of electric current. The body of the bulb is made airtight to prevent the entry of air which could lead to oxidation and deterioration of the filament. The electric supply is maintained by the batteries. All these components are enclosed in a sturdy package. The bulb is safely affixed behind a glass shield. The electrical circuitry is controlled with an ON/OFF switch provided. Most flashlights are normally cylindrical with the light assembly occupying one end.

 Some flashlights have a flat base on which the device stands. The direction of the light beam can be changed with a two-position pivoting head facility. The intensity of the beam can also be adjusted depending on the lighting in the area and also on the battery charge. Flashlights normally use a voltage of around 12 volts.

Some flashlights use light emitting diodes (LED’s) instead of incandescent bulbs. This form of illumination utilizes less power than incandescent bulbs. Thus, LED using flashlights generally have a longer battery life. Additionally, LED’s are more resistant to hard impacts as compared to incandescent bulbs which tend to shatter at the slightest impact. LED’s are also electronically controlled for constant light emission even when the battery charge is fading.

For better performance, some flashlights have 16 individual LEDs and 16 reflector tubes. The reflector tubes and a light chip offer a high intensity light beam. Durability is further enhanced with 24 carat gold contacts. Some LED flashlights have three light modes with a micro-faceted reflector for a smooth focused beam. The focus can be changed and the device is computer machined.

Flashlights mounted on worker’s helmets are called headlamps and are often used by miners and other underground laborers. This concept also keeps the worker’s hands free, which is necessary when working in precarious locations. 

Generally flashlights are easy to use and have changeable brightness Levels, variable optics, and dive-depth waterproof ratings. Torch shaped flashlights are around 10 inches in length. Three N-cell alkaline batteries offer around 120 hours of uninterrupted usage.

Some flashlights are shaped like conventional lanterns illuminating a wide area. An intrinsic telescopic hook rotates around 360 degrees and allowing the unit to either be hung or placed on a surface. An over-molded lens cover offers better durability. The lens cover has a tool free twist and lock mechanism that enables fast and simple bulb changing. A pre-heated circuit prevents any blackening at the bottom of the bulb.

Certain flashlights have dual functionality offering both LED and Xenon operation, with the LED’s offering around 80 hours run time and the Xenon facility offering around 2.5 to 3 hours run time.

Certain flashlights having a rubberized waterproof coating are designed to be used underwater. These tools generally have an aluminum reflector that emits a strong and narrow beam for light penetration over a longer distance through the water.

What to look for in a flashlight

A flashlight with a stand is an added advantage as it is able to rest on a fat surface and it frees both the user’s hands for the intended task. Generally, flashlights are shipped with two extra bulbs. One extra light can be kept inside the handle itself. Powerful LED flashlights may emit a certain amount of heat and therefore, they are usually housed in metal, fiber glass, or rubber enclosed cases.  

The grip is ergonomically contoured and sometimes knurled for better user comfort. A push button switch makes usage very convenient. Some flashlights have a lanyard included.

The stainless steel casing of a flashlight is made shockproof and water resistant. Sometimes the flashlight may be shipped in a zippered nylon case with a transparent plastic space allowing the light to shine through without the case being removed. Some reputed manufacturers of flashlights include Bosch, Coast Tek, DeWalt, and Streamlight.