flashlight

A flashlight, or torch in many countries, is a portable hand-held light powered by batteries. It typically contains a light source, a power source, and a housing with a switch. When activated, electrical energy is converted into visible light, usually by a light-emitting diode (LED) in modern models. Lenses and reflectors shape the beam and may offer multiple brightness levels.

The first portable electric torches appeared in the late 19th century. In 1899 British inventor David Misell introduced a device powered by disposable dry cells and an incandescent bulb. Early models used simple casings and carbon-zinc cells. The term flashlight is common in the United States; elsewhere the word torch is used. The LED era began in the early 2000s, increasing efficiency.

Components and design: The main parts are the power source (batteries), the light source (lamp or LED), a reflector and lens to shape the beam, and a control switch. Housings are typically aluminum or durable plastic, designed to be lightweight, impact-resistant, and sometimes water-resistant.

Types and features: Common forms include handheld flashlights, headlamps, and tactical models. Modern flashlights offer multiple brightness modes, low power and strobe or SOS settings, and many are rechargeable via USB. Battery types range from disposable alkaline to rechargeable Li-ion or NiMH cells.

Performance and standards: Brightness is described in lumens, with beam distance and run time reported under standardized testing such as ANSI/NEMA FL1. Durability ratings include impact resistance and water resistance (IP ratings). Safety considerations include proper charging, storage, and disposal of batteries.

Uses: Flashlights are used in daily tasks, outdoor activities, emergencies, industrial work, and rescue operations.