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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 ...
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.
Color corrected" mercury bulbs overcome this problem with a phosphor on the inside of the outer bulb that emits at the red wavelengths, offering whiter light and better color rendition. Mercury-vapor lights operate at an internal pressure of around one atmosphere and require special fixtures, as well as an electrical ballast. They also require ...
This energy is partially absorbed and scattered in the atmosphere, the latter process being the reason why the sky is visibly blue. [3] Much of the Sun's radiation transmits through the atmosphere to the surface where it is either absorbed or reflected. Thermal radiation can be used to detect objects or phenomena normally invisible to the human ...
At low frequencies, as the time period of the Wien bridge oscillator approaches the thermal time constant of the incandescent bulb, the circuit operation becomes more nonlinear, and the output distortion rises significantly. Light bulbs have their disadvantages when used as gain control elements in Wien bridge oscillators, most notably a very ...
The heat deflection temperature or heat distortion temperature (HDT, HDTUL, or DTUL) is the temperature at which a polymer or plastic sample deforms under a specified load. [1] This property of a given plastic material is applied in many aspects of product design, engineering and manufacture of products using thermoplastic components.
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 ...
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.