subject: What Is An Led? And What Makes It So Energy Efficient? [print this page] Light emitting diode is a semi conductor light source used in many devices. When a light emitting diode is triggered or it is switched on, the electrons are able to recombine with the electron holes situated in the device. This results into the release of energy in the form of photons. The effect is called electroluminescence and the color of the light is determined by the gap of the light in the semi conductor. LED is as small as 1mm. sq.
LEDs are designed to operate with only 30 to 60 milliwatts of electrical power. One of the key advantages of LED lights is its high efficiency. White LED operated at 5 watts also. Further these are available with luminous efficiency of 18-22 lumens per watt. A conventional bulb operates at between 60-100 W or at least at 40W giving out a very weak light, and emits 15lm/W. The FCL bulb generated up to 100lm/W. A very important factor is that efficiency decreases with the rising current. This factor is called the droop.
In the early years of the 21st century, a new type of Blue LED was introduced. This was meant to produce 24mW at 20 mill amperes but practically it produced 65 lm/W at 20 mA. Further models produced 131 lm/W and 145 lm/W. A bulb was produced with a luminous efficiency of 150 ml/W. Thus it had low energy consumption and produced more light.
Efficiency factor is also due to its lack of use of metal filament for the light generation. As the electrons are transmitted and there is no physical elements were involved to sustain the heat, that is why it offers minimum resistance and this cuts down the need for more power.
They are available in various colors, such as green, yellow, red, blue, and white. The above given scores are a lab based tests, as they were conducted under minus temperature and ideal conditions. Practically, they produced an efficiency test result between 17 ml/W to 79 m/W.
The lens in front of the illumination point within the LED projects light. This is called a solid state light, or the solid light. The basic structure includes the following parts:
