Search results
Results From The WOW.Com Content Network
Free electrons are in the conduction band of energy levels, while holes are in the valence energy band. Thus the energy level of the holes is lower than the energy levels of the electrons. Some portion of the energy must be dissipated to recombine the electrons and the holes. This energy is emitted in the form of heat and light.
Most of the electricity in an LED becomes heat rather than light – about 70% heat and 30% light. [1] If this heat is not removed, the LEDs run at high temperatures, which not only lowers their efficiency, but also makes the LED less reliable, shortens its lifespan. Thus, thermal management of high power LEDs is a crucial area of the research ...
Contaminants, because they absorb more light and heat than the glass does, will create a hot spot on the bulb surface when the lamp is turned on. This extreme, localized heat causes the quartz to change from its vitreous form into a weaker, crystalline form that leaks gas. This weakening may also cause the bulb to form a bubble, weakening it ...
In a light-emitting diode, the recombination of electrons and electron holes in a semiconductor produces light (be it infrared, visible or UV), a process called "electroluminescence". The wavelength of the light depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of ...
Photon-enhanced thermionic emission (PETE) is a process developed by scientists at Stanford University that harnesses both the light and heat of the sun to generate electricity and increases the efficiency of solar power production by more than twice the current levels.
A heat lamp is an incandescent light bulb that is used for the principal purpose of creating heat. The spectrum of black-body radiation emitted by the lamp is shifted to produce more infrared light. Many heat lamps include a red filter to minimize the amount of visible light emitted. Heat lamps often include an internal reflector.
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a filament that is heated until it glows. The filament is enclosed in a glass bulb that is either evacuated or filled with inert gas to protect the filament from oxidation. Electric current is supplied to the filament by terminals or wires ...
They give light immediately on startup, but usually need a few minutes to restrike if power has been interrupted. Because of the light emitted by the filament, they have slightly better color rendering properties than mercury-vapor lamps. Self-ballasted lamps are typically more expensive than a standard mercury-vapor lamp.