Flashlights

A flashlight, also known as a torch in some regions, is a portable handheld electric light. It is designed to emit light for visibility in darkness and during power outages, outdoor activities, work tasks, and emergency situations.

Flashlights consist of a light source, a power source, and a rechargeable or disposable housing with a switch and optical elements. The light source is typically an LED in modern models; earlier flashlights used incandescent bulbs. The power source is usually disposable batteries or rechargeable cells; common chemistries include alkaline, nickel-metal hydride, and lithium-ion. Some flashlights have interchangeable batteries or built-in rechargeable packs. The housing may be made of plastic or metal and may include weather sealing and impact resistance. Optical features include reflectors and lenses to shape the beam and control focus.

Performance is described by brightness in lumens, run-time, and beam distance. LEDs offer long life and high efficiency; high-lumen models are used for search or outdoor use, and lower-lumen modes extend battery life. Many flashlights provide multiple output levels and modes, such as adjustable brightness, strobe, or SOS signals. Waterproof ratings (IPX) and impact resistance (drop tests) affect suitability for rugged use.

Types include handheld flashlights, headlamps, penlights, and duty or tactical flashlights. They vary in size from compact keychain models to large handheld units. Common applications include camping, home and automotive use, professional service work, and emergency preparedness.

A brief history: The first flashlight was developed in the late 19th century; in 1899, David Misell introduced the first portable electric flashlight powered by three batteries. Modern developments have concentrated on light-emitting diodes (LEDs) and improved battery chemistry, enabling compact, durable, high-performance devices with long run times.