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Two modern electric lamps with lampshades. A lampshade is a fixture that envelops the light bulb on a lamp to redirect the light it emits. The shade is often affixed onto a light fixture to reduce the intensity of the light to observers, shield the light from a harsh environment, or for decoration by altering the color or creating shadows.
LED power dissipation is modeled as a current source; thermal resistance is modeled as a resistor; and the ambient temperature is modeled as a voltage source. High power light-emitting diodes (LEDs) can use 350 milliwatts or more in a single LED. Most of the electricity in an LED becomes heat rather than light – about 70% heat and 30% light. [1]
Reverse bias: Although the LED is based on a diode junction and is nominally a rectifier, the reverse-breakdown mode for some types can occur at very low voltages and essentially any excess reverse bias can cause immediate degradation, and may lead to vastly accelerated failure. 5 V is a typical maximum reverse bias voltage specification for ...
LED Light Buzzing Fixes. The primary cause of a buzzing LED light bulb is a discrepancy between the bulb wattage and that of the switch or dimmer. While this isn't dangerous, it can be really ...
If an LED lamp does not have free air circulation, the LED is likely to overheat, resulting in reduced life or early failure. The thermal design of the system must allow for the ambient temperature surrounding the lamp; a lamp in a freezer experiences a lower ambient than a lamp in a billboard in a sunny climate.
A 230-volt LED filament lamp, with an E27 base. The filaments are visible as the eight yellow vertical lines. An assortment of LED lamps commercially available in 2010: floodlight fixtures (left), reading light (center), household lamps (center right and bottom), and low-power accent light (right) applications An 80W Chips on board (COB) LED module from an industrial light luminaire, thermally ...
Often more than half of the emitted light is reflected back at the LED-package and package-air interfaces. The reflection is most commonly reduced by using a dome-shaped (half-sphere) package with the diode in the center so that the outgoing light rays strike the surface perpendicularly , at which angle the reflection is minimized.
Solid-state lighting (SSL) is a type of lighting that uses semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma (used in arc lamps such as fluorescent lamps), or gas.