The LEDs or Light Emitting Diodes emit light when electric current is passed through them. The LED is a solid state device that needs low voltage and cannot directly operate on AC current without connecting into a circuitry which can control the voltage.
- LEDs are available in a wide variety of sizes and shapes. The standard LED has a round cross-section of about 5 mm diameter.
- LEDs are also available in different colors like red, orange, amber, yellow, green, blue and white.
- Also, Bi-color LEDs, which means two LEDs wired in inverse parallel and Tri-color LEDs which means a red and a green LED combined in one package with three leads, are quite popular. In Bi-color LEDs, only one of LEDs can be lit at a time while in Tri-color LEDs light is generated when both red & green LEDs are turned on.
- LEDs are very efficient, as they generate very less heat when turned on, hence consume less energy, thereby increasing their lifetime. Under normal conditions, most LEDs have a lifetime of 1,00,000 hours. LEDs are also very rugged. Also, they do not emit UV rays or contain any toxins.
- LEDs are very small in size thus can be combined in different shapes to get different effects.
To generate white light, sometimes red, green & blue LEDs are used which is called multi-colored white LEDs or RGB LEDs. Alternatively, Phosphor-based white LEDs, which are made by coating LED of one color with phosphor of different colors to form white color. The Phosphor based white LED method of generating white color is the most popularly used method.