| rdfs:comment
| - A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
- A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
* lower energy consumption
* longer lifetime
* improved robustness
* smaller size
* faster switching
* greater durability and reliability.
- When a Transformer toy is equipped with electric lights, the light is not usually provided by a light bulb, but by a light-emitting diode or LED. These small devices glow when electrified. They work, like most electronic devices, by virtue of the magic smoke which is sealed inside them at the factory, but (as usual) the wicked scientists have (in their blind ignorance) provided their own explanation for us to scoff at.
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| abstract
| - A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
- A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness. When a light-emitting diode is forward biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons (light). This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including:
* lower energy consumption
* longer lifetime
* improved robustness
* smaller size
* faster switching
* greater durability and reliability. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output. Light-emitting diodes are used in applications as diverse as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances.
- When a Transformer toy is equipped with electric lights, the light is not usually provided by a light bulb, but by a light-emitting diode or LED. These small devices glow when electrified. They work, like most electronic devices, by virtue of the magic smoke which is sealed inside them at the factory, but (as usual) the wicked scientists have (in their blind ignorance) provided their own explanation for us to scoff at. They claim that the light emitted is caused by the interaction of electrons and 'holes' at the junction of P and N-type semiconductors inside the diode (the junction which allows a diode to act as a 'valve', conducting electricity in only one direction). It is interesting to note that the color of this light depends on the design of the LED, and that it is produced in a very narrow band of the spectrum, not the wide range of simultaneous frequencies emitted by other light sources such as bulbs. The observed color, therefore, can not easily be changed by filters. It is also interesting to note that red LEDs use gallium arsenide, which has appeared elsewhere in Transformers lore. Because LEDs are small components with minimal power requirements, it is not uncommon to see one (or more) integrated onto the boards of a Soundbox, creating the proverbial light and sound show.
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