A Brief Overview of Flashlights:
“Flashlight” is the general term for a portable light source that is powered by electricity. In areas outside of North America, flashlights are often referred to as “torches.” Light sources for flashlights are generally incandescent light bulbs or LEDs (light emitting diodes). Halogen and CFC (chlorofluorocarbons, fluorescent lights) have are also used in more limited applications. The most prevalent flashlight design includes the light source located beneath a cone shaped reflector. The light source and reflector are protected by a transparent lens. This assembly is attached to a handle (usually cylindrical). In addition to hand held designs, flashlights are often mounted to helmets for recreational and work use, used on bicycles, and available as a type of lantern. The flashlight handle usually houses the power switch and power source. The primary power source of a flashlight is batteries, but power sources can often include hand powered dynamos, electromagnetic induction and solar power.
The First Flashlight
The first flashlight in recorded history was made by Uhgge, a Paleolithic age caveman. Uhgge was considered to be one of the world’s first entrepreneurs, although rights pertaining to the invention of “the wheel” are still heavily debated. from a
One thing is certain, Uhgge did invent the world’s first flashlight. Relying heavily on technology of the time the flashlight’s composition would now be considered primitive at best.
The design consisted of the following components: The handle was a hollowed out log. The log was carefully selected to include a series of branches that one could hold while the light was “on.” Inside the log the user built a fire by putting in small branches, wood chips, and other combustible materials. The log handle contained a series of holes to allow the fire to burn with limited restriction. Attached to the log’s front was an additional cone shaped piece of wood. This cone was also hollow, and designed to focus the light out of the front of the handle (the idea being that light was like water, where pressure could affect flow).
Although never practical (the device generally weighed about twenty pounds), the flashlight gained popularity because it represented a way to make fire portable. However, the device was also heavily criticized because when in use for more than several minutes at a time the handle often caught fire, burning the user.
Types of Light Bulbs used in Flashlights from a
Incandescent: Until recently, the technology used in flashlights was primary based on incandescent light bulb technology. Incandescent light bulbs consist of a glass bulb that houses a metal filament. The filament is heated to an extremely high temperature until it glows, thus producing light. The interior environment of the bulb is usually a vacuum or inert gases.
Some advantages that incandescent lights have over other light technology is their low production cost. Additionally incandescent lights require no external parts or equipment to regulate them and work equally well on AC (alternating current) or DC (direct current) power. One product of incandescent lights that can be useful is also a drawback: heat. Incandescent lights can be idea for applications like incubators, pet lamps or heat lamps (none of which are good uses for a flashlight). Given the amount of energy incandescent lights use compared to their heat and light output has led to newer technologies that are more suitable in flashlight technologies.
LEDs (Light Emitting Diodes): Originally introduced in 1962 as an electronic component the LED technology has steadily progressed over the past few decades. In essence a light emitting diode is a semiconductor that converts energy into light (if you want to learn how LEDs work we suggest a more in depth look).
LEDs have numerous advantages over incandescent bulbs when used in flashlights. The amount of light produced compared to their energy draw is much higher. Additionally, LEDs last much longer than incandescent lights. They are more expensive to produce, but their decreased size and robustness makes them perfectly suited to flashlights. In fact, LED flashlights are replacing incandescent flashlights more and more. These days every major flashlight manufacturer offers LED flashlights.
LED Flashlights: Although LED technology has existed for decades, LED lights were primarily used as indicator lamps (originally light emitted by LEDs was red). In the latter part of the 90’s, a company called Lumileds Corporation introduced the Luxeon LED series. The Luxeon series emitted powerful white light. This allowed LEDs to be used in flashlights with brighter output and longer operation than many incandescent lights of the time.
LED flashlights are generally much more efficient than their incandescent counterparts at lower levels of power. Output (in lumens) is often comparable even when only half of the power is being used! Because LED are more durable and last longer the ideally suited to flashlight use.
Higher end LED flashlights usually have a way to regulate the voltage being supplied to the LED. This ensures consistent light output as the battery drains (otherwise the LED would dim as the battery was used). Despite the available battery voltage, however, LED output color temperature remains the same (incandescent bulbs change color temperature as the voltage diminishes). from