27/04/2015
All you always wanted to know about LED lights but never dared to ask ;)
LED = Light Emitting Diode.
* General Comparison
LEDs and light bulbs have completely different characteristics!
LED advantages
- Brightness: LEDs produce more light per watt than the normal light bulb, which means that LEDs produce a lot of light and little heat whereas normal light bulbs produce a lot of heat for a little light.
- Energy-Efficiency: LEDs consume less energy than normal light bulbs for the same brightness and have a longer life expectancy (100 000 hours) as opposed to normal light bulbs (some thousands of hours).
- Durability: LEDs are much less susceptible to damage than normal light bulbs.
Normal Light Bulb Advantages
- While LEDs lighting is directional (great for a flashlight), normal light bulbs have a broader range (great for lighting a room).
- Normal light bulbs are cheaper than LEDs.
- Normal light bulbs work on direct and alternating current whereas LEDs always need alternating current at a precise setting.
- Normal light bulbs are not susceptible to static overheating whereas LEDs must be protected from it.
Brightness Comparison
The brightness of a normal light bulb is between 8 and 18 lumen per watt, depending on several criteria, for example, the age of the bulb. The light has a spherical shape.
8 lumens per watt is equivalent to 100 Watts = 800 lumens.
Lumen
The word ‘Lumen’ means the quantity of light emitted by a light source with an intensity of 1 candela, located in an angle and lighting a space of 1m2 at a distance of 1m.
Just remember that 1 lumen = 1 candela = 1 candle.
The efficiency of a light can also be measured in lumens per watt (lm/W).
Lux
The word ‘Lux’ means the net measure of the light through a specific light measure device. It is used to calculate the ‘lumen’. 1 lux means 1 lumen/m2.
Mcd or milli-candela
The brightness of an LED can be measured in milli-candela.
One candela is the bright intensity which lights 1/600 000m² of the surface of a « black blip » in the temperature of a platinum hung at right angles on its surface, this one weighing 101325kg/ms².
To simplify the previous mathematic formula, you just need to know that a candela has approximately the lighting intensity of a candle.
Starting angle (in degree °)
Light is produced by regular LEDs of 5mm and 3mm in a conic shape. So the angle indicates the opening of the cone.
There are two exceptions:
- Diffused LEDs that don’t light so much.
- Oval LEDs that have two angles. The wider the angle is, the bigger the lighting surface will be.
