A flashlight or torch is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the mid-2000s. A typical flashlight consists of the light source mounted in a reflector, a transparent cover to protect the light source and reflector, a battery, and a switch, all enclosed in a case.
Photometry is the science of the measurement of light, in terms of its perceived brightness to the human eye. It is distinct from radiometry, which is the science of measurement of radiant energy in terms of absolute power. In modern photometry, the radiant power at each wavelength is weighted by a luminosity function that models human brightness sensitivity. Typically, this weighting function is the photopic sensitivity function, although the scotopic function or other functions may also be applied in the same way.
Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.
The lumen is the unit of luminous flux, a measure of the total quantity of visible light emitted by a source per unit of time, in the International System of Units (SI). Luminous flux differs from power in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model of the human eye's sensitivity to various wavelengths. One lux is one lumen per square metre.
A primary battery or primary cell is a battery that is designed to be used once and discarded, and not recharged with electricity and reused like a secondary cell. In general, the electrochemical reaction occurring in the cell is not reversible, rendering the cell unrechargeable. As a primary cell is used, chemical reactions in the battery use up the chemicals that generate the power; when they are gone, the battery stops producing electricity. In contrast, in a secondary cell, the reaction can be reversed by running a current into the cell with a battery charger to recharge it, regenerating the chemical reactants. Primary cells are made in a range of standard sizes to power small household appliances such as flashlights and portable radios.
A tactical light is a flashlight used in conjunction with a firearm to aid low-light target identification, allowing the user to simultaneously aim a weapon and illuminate the target.
An emergency light is a battery-backed lighting device that switches on automatically when a building experiences a power outage.
The AA battery is a standard size single cell cylindrical dry battery. The IEC 60086 system calls the size R6, and ANSI C18 calls it 15. It is named UM-3 by JIS of Japan. Historically, it is known as D14, U12 – later U7, or HP7 in official documentation in the United Kingdom, or a pen cell.
SureFire, LLC. is an American company headquartered in Fountain Valley, California. Their main products are flashlights, weapon-mounted lights, headlamps, and laser sights. In addition, Surefire produces knives, sound suppressors, earplugs, Picatinny Rails, high capacity magazines, and batteries. The company is a major supplier of flashlights, weapon lights, and lasers to the U.S. Armed Forces and its allies, especially for elite special operations groups such as the Navy SEALs. Surefire products are widely used in the U.S. by law enforcement agencies and SWAT teams.
A mechanically powered flashlight is a flashlight that is powered by electricity generated by the muscle power of the user, so it does not need replacement of batteries, or recharging from an electrical source. There are several types which use different operating mechanisms. They use different motions to generate the required power; such as squeezing a handle, winding a crank, or shaking the flashlight itself. These flashlights can also be distinguished by the technique used to store the energy: a spring, a flywheel, a battery or a capacitor.
A battery charger, recharger, or simply charger, is a device that stores energy in a battery by running an electric current through it. The charging protocol depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle. Other battery types use a timer to cut off when charging should be complete. Other battery types cannot withstand over-charging, becoming damaged, over heating or even exploding. The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge. Chargers may elevate the output voltage proportionally with current to compensate for impedance in the wires.
Eveready Industries India Ltd. (EIIL) is an Indian company that manufactures and markets Batteries, Flashlights, Lighting solutions. The Eveready brand has been present in India since 1905. EIIL's principal activities are the manufacture and market of batteries, flashlight cases, electrolytic manganese dioxide and arc carbons. It also manufactures photo-engravers plates/strips for printing, castings, hard facing and tube rods, carbon electrodes and other related products.
A rechargeable alkaline battery, also known as alkaline rechargeable or rechargeable alkaline manganese (RAM), is a type of alkaline battery that is capable of recharging for repeated use. The formats include AAA, AA, C, D, and snap-on 9-volt batteries. Rechargeable alkaline batteries are manufactured fully charged and have the ability to hold their charge for years, longer than NiCd and NiMH batteries, which self-discharge. Rechargeable alkaline batteries can have a high recharging efficiency and have less environmental impact than disposable cells.
An LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and can be significantly more than most fluorescent lamps. The most efficient commercially available LED lamps have efficiencies of 200 lumen per watt (Lm/W). Commercial LED lamps have a lifespan many times longer than incandescent lamps.
Kel-Lite was the first heavy-duty aluminum bodied flashlight, which became popular with law enforcement agencies due to its heavy construction. They were designed to be carried in place of a police baton and also provide light. The eponymous company, founded by Donald Keller and Frank Patti in 1968, manufactured Kel-Lite flashlights in southern California until 1983, when the company was merged into Streamlight.
Eneloop is a brand of 1.2-volt low self-discharge nickel–metal hydride (NiMH) rechargeable batteries and accessories developed by Sanyo and introduced in 2005. Panasonic acquired a majority stake in Sanyo in 2009, and Eneloop batteries were thereafter branded, but not manufactured, by Panasonic.
A headlamp or headlight is a light source affixed to the head for outdoor activities at night or in dark conditions such as caving, orienteering, hiking, skiing, backpacking, camping, mountaineering or mountain biking. Headlamps may also be used in adventure races. Headlamps are often used by workers in underground mining, search and rescue, surgeons, and by other workers who need hands-free lighting.
Solar powered flashlights or solar powered torches are flashlights powered by solar energy stored in rechargeable batteries. Most of these flashlights use light-emitting diodes lamps since they have lower energy consumption compared to incandescent light bulbs.
A dive light is a light source carried by an underwater diver to illuminate the underwater environment. Scuba divers generally carry self-contained lights, but surface supplied divers may carry lights powered by cable supply.
The MX-991/U Flashlight is a right-angle-head flashlight developed from the TL-122 military flashlight series of 1937-1944 and is a development of the MX-99/U flashlight issued in 1963. Produced since the Vietnam era, the MX-991/U has been made by various contractors over the years, including GT Price, Bright Star, and Fulton Industries. MX-991/U flashlights currently issued to the United States Army and United States Marines are produced by Fulton Industries. The flashlight's signature right angle design has proved popular in civilian use.
