There are a few ways you can turn your flashlight on or off. You can ask Siri, or you can use Control Center on an iPhone with Face ID or an iPad Pro. Or use Control Center with an iPhone with a Home button.
Shed light on black box machine learning models by the help of model performance, variable importance, global surrogate models, ICE profiles, partial dependence (Friedman J. H. (2001) ), accumulated local effects (Apley D. W. (2016) ), further effects plots, scatter plots, interaction strength, and variable contribution breakdown (approximate SHAP) for single observations (Gosiewska and Biecek (2019) ). All tools are implemented to work with case weights and allow for stratified analysis. Furthermore, multiple flashlights can be combined and analyzed together.
Flashlights can get very expensive, so for a light powered by two AA batteries, we set a price limit of about $40. There is an enormous world of flashlights that cost more, but at this price, we knew we could find an entry-level version of an enthusiast light that offered some of the most important features standard on the higher-end lights. Unfortunately, our cutoff excluded many manufacturers that were favorites of the flashlight crowd (as well as among police officers, firefighters, and others in public safety), notably Elzetta, Fenix, Foursevens, and SureFire.
Instead of taking more meter readings in a sealed, lab-like, dark room, I spent night after night after night wandering around the dark New Hampshire woods (and more than once caught the reflection of animal eyes looking back at me). We tested in the weeks surrounding a new moon and in an area with very little light pollution. This unstructured testing gave us the most useful gauge of overall usability, beam spread, and beam distance, and it really helped us understand what each light had to offer from a practical standpoint. We also used the flashlights for more regular daily tasks, such as looking under the couch for Legos, checking the crawl space for signs of mice, and investigating strange nighttime noises in the backyard. Lastly, we used the lights during multiple power outages.
Speaking of drops, the Archer 2A V3 is rated for a 1-meter fall. Many flashlights we tested also came with an IPX rating indicating the standard for protection against water intrusion. The Archer 2A V3 has the highest rating of IPX8, meaning it can tolerate being completely submerged in water over 2 meters deep (which we put it through a number of times to no ill effect). The tested lights from Manker and Nitecore have the same water-intrusion rating as this ThruNite model.
With this setup, we found it very easy to regularly keep the Olight fully charged. All we had to do was set the light down right near the charging cord, and it would attach itself. Additionally, we were impressed with the overall feel and quality of the S2R Baton II. It typically costs around $70, which is still less than the price of most quality rechargeable flashlights.
The Olight Warrior Mini 2 is an excellent light and has the interesting ability to auto-dim if an object is too close to the lens, to prevent overheating in a backpack or a pocket. Typically $20 more expensive than the Olight S2R Baton II, this model is brighter and offers a longer battery life. It has both a side button and a tail switch, which control different settings and can get confusing. If you use a flashlight enough to keep these button modes top of mind, this light provides a lot of versatility. During more casual use in our tests, however, we kept forgetting the nuances of the buttons and often ended up grabbing another flashlight with a simpler interface.
A flashlight (US, CA) or torch (UK, AU) 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 (sometimes combined with a lens) to protect the light source and reflector, a battery, and a switch, all enclosed in a case.
The invention of the dry cell and miniature incandescent electric lamps made the first battery-powered flashlights possible around 1899. Today, flashlights use mostly light-emitting diodes and run on disposable or rechargeable batteries. Some are powered by the user turning a crank, shaking the lamp, or squeezing it. Some have solar panels to recharge the battery. Flashlights are used as a light source outdoors, in places without permanently installed lighting, during power outages, or when a portable light source is needed.
In addition to the general-purpose, hand-held flashlight, many forms have been adapted for special uses. Head- or helmet-mounted flashlights designed for miners and campers leave the hands free. Some flashlights can be used under water or in flammable atmospheres.
Carbon-filament bulbs and fairly crude dry cells made early flashlights an expensive novelty, with low sales and low manufacturer interest. Development of the tungsten-filament lamp in 1904, with three times the efficacy of carbon filament types, and improved batteries, made flashlights more useful and popular. The advantage of instant control, and the absence of flame, meant that hand-held electric lights began to replace combustion-based lamps such as the hurricane lantern. By 1922 several types were available; the tubular hand-held variety, a lantern style that could be set down for extended use, pocket-size lamps for close work, and large reflector searchlight-type lamps for lighting distant objects. In 1922 there were an estimated 10 million flashlight users in the United States, with annual sales of renewal batteries and flashlights at $20 million, comparable to sales of many line-operated electrical appliances. Flashlights became very popular in China; by the end of the 1930s, 60 companies made flashlights, some selling for as little as one-third the cost of equivalent imported models. Miniature lamps developed for flashlight and automotive uses became an important sector of the incandescent lamp manufacturing business.
Incandescent flashlights use incandescent light bulbs, which consists of a glass bulb and a tungsten filament. The bulbs are under vacuum or filled with argon, krypton, or xenon. Some high-power incandescent flashlights use a halogen lamp where the bulb contains a halogen gas such as iodine or bromine to improve the life and efficacy of the bulb. In all but disposable or novelty flashlights, the bulb is user-replaceable; the bulb life may be only a few hours.
The light output of an incandescent lamp in a flashlight varies widely depending on the type of lamp. A miniature keychain lamp produces one or two lumens. A two-D-cell flashlight using a common prefocus-style miniature lamp produces on the order of 15 to 20 lumens of light and a beam of about 200 candlepower. One popular make of rechargeable focusing flashlight uses a halogen lamp and produces 218 lumens. By comparison, a 60-watt household incandescent lamp will produce about 900 lumens. The luminous efficacy or lumens produced per watt of input of flashlight bulbs varies over the approximate range of 8 to 22 lumens/watt, depending on the size of the bulb and the fill gas, with halogen-filled 12-volt lamps having the highest efficiency.
Powerful white-light-emitting diodes (LEDs) have mostly replaced incandescent bulbs in practical flashlights. LEDs existed for decades, mainly as low-power indicator lights. In 1999, Lumileds Corporation of San Jose, California, introduced the Luxeon LED, a high-power white-light emitter. This made possible LED flashlights with power and running time better than incandescent lights. The first Luxeon LED flashlight was the Arc LS, designed in 2001. White LEDs in 5 mm diameter packages produce only a few lumens each; many units may be grouped together to provide additional light. Higher-power LEDs, drawing more than 100 milliamperes each, simplify the optical design problem of producing a powerful and tightly controlled beam.
LEDs can be significantly more efficient than incandescent lamps, with white LEDs producing on the order of 100 lumens for every watt, compared to 8-10 lumens per watt of small incandescent bulbs. An LED flashlight has a longer battery life than an incandescent flashlight with comparable output. LEDs are also less fragile than glass lamps. LED lamps have different spectra of light compared to incandescent sources, and are made in several ranges of color temperature and color rendering index. Since the LED has a long life compared to the usual life of a flashlight, very often it is permanently installed. Flashlights made for an incandescent lamp can often be upgraded to a more efficient LED lamp.
LEDs generally must have some kind of control to limit current through the diode. Flashlights using one or two disposable 1.5-volt cells require a boost converter to provide the higher voltage required by a white LED, which needs around 3.4 volts to function. Flashlights using three or more dry cells may only use a resistor to limit current. Some flashlights electronically regulate the current through the LEDs to stabilize light output as the batteries discharge. LEDs maintain nearly constant color temperature regardless of input voltage or current, while the color temperature of an incandescent bulb rapidly declines as the battery discharges, becoming redder and less visible. Regulated LED flashlights may also have user-selectable levels of output appropriate to a task, for example, low light for reading a map and high output for checking a road sign. This would be difficult to do with a single incandescent bulb since efficacy of the lamp drops rapidly at low output.
LED flashlights may consume 1 watt or much more from the battery, producing heat as well as light. In contrast to tungsten filaments, which must be hot to produce light, both the light output and the life of an LED decrease with temperature. Heat dissipation for the LED often dictates that small, high-power LED flashlights have aluminium or other high heat-conductivity bodies, reflectors, and other parts to dissipate heat; they can become warm during use. 041b061a72