As LED lighting is becoming increasingly popular in architectural lighting, task lighting, medical lighting (particularly for use in surgical theatres), transportation, entertainment, and even household lighting greenrecord.co.uk This article intends to be a comprehensive guide to their utility, what the advantages that LED lighting possesses over other types of lighting and how to select an appropriate power source for the LED lights.
First, what IS an LED light? A light-emitting diode (LED) is an electronic light source. LED’s are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor.
LED’s present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size ( enabling LED’s to be easily populated onto printed circuit boards.) and faster switching (LED’s light up very quickly. A typical red indicator LED will achieve full brightness in microseconds, and LED’s used in communications devices can have even faster response times.). Thus their utility value is very high. Maybe the greatest advantage of all is that as the color of the light depends on a specific variable (i.e.- the energy gap of the semiconductor) thus LED’s can emit light of an intended color without the use of color filters that traditional lighting methods require. This is more efficient and can lower initial costs for a vast range of applications which previously used the colour filtering process.
Further advantages of LED’s exist, among them efficiency of an LED is prominent. LED’s produce more light per watt than incandescent bulbs, and wastage of energy is minimal, as LED’s radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as heat through the base of the LED. Further as light is emitted from a solid state material, greater shock absorption capability is present in the LED lights. Further, LED’s do not contain mercury, unlike most fluorescent lamps.
But LED’s are currently more expensive, on an initial capital cost basis, than most conventional lighting technologies, and are very much sensitive to temperature and voltage. LED’s must be supplied with the voltage above the threshold and a current below the rating. This can involve series resistors or current-regulated power supplies, and the proper function of the power supply is an essential factor in creating maximum utility and longevity of the systems. If too much current passes through the semiconductor material forming the Diodes the LED will burn out! LED power supplies must, among others, provide Universal AC input, allowing the full range of applications, Short circuit, over load, over voltage protection, a built-in dimming function, allowing the light levels to be adjusted to create different effects.
And of course the safety of the LED power supply is a prime concern, to prevent overheating, cooling should take place, and the most efficient form of this is by free air convection. And the power supply must come fully equipped with an isolated, (preferably) plastic case that is resistant to external influences such as water on order to protect it from harmful effects of water and dust.
If you are planning an LED lighting project, for your home, garden or even your office or your shop, a