In order to explain how an LED works we must explain the four main components of an LED lamp; the LED Chip, the Driver, the The LED chip emits lights the in the bulb. Heat Sink, and the Optic lens.
The driver then regulates the input current.
The Heat Sink draws the heat away from the LED Chip.
The optic controls the characteristics of the light output.
LED chip - which stands for Light Emitting Diode, is a light source that becomes illuminated by the movement of electrons or an electrical current passing through a semiconductor material. A semiconductor is a substance, usually a solid chemical element or compound that can conduct electricity under some conditions making it a good medium to control an electrical current.
Solid State Lighting (SSL) - is lighting that uses LED’s. Because it is a sold state lighting, it does not require a heated filament, like an incandescent bulb. An LED light is formed when bringing an P-Type (+) and a N-Type (-) semiconductors that form a PN Junction. Energy is released in the form of light when The N-Type (-) electrons and the P-Type (+) positively charge holes are combined.
An LED driver - regulates the current flowing through the LED, similar to a ballast in a compact fluorescent lights.LED drivers can be internal or external. LED Light output is proportional to its current; any slight variation in the current can result in unacceptable changes in light output. So the led driver is a very key component the light output and greatly impacts the lamp life of the LED.
The heat sink - is a key component in a good quality LED. LEDs do not generate much external ambient heat but they do generate internal heat within the junction, High temperatures near the LED junction affect the short term and long term life and affect the LED performance. Heat must be removed from the LED Chip to maintain expected light output, life, and color. Short terms effects of improper heat sinking would be lower light output, and also a wavelength color shift, while the long-term effects would be a lower lamp life. The heat sink is essential to removing heat which is removed through convection (by air) or by conduction (by contact). Most metals are excellent conductors which why they are used as mounting materials for most LED’s.
The Optic - is also a big component of an LED lamp, which has multi-level optics.
The Primary Optic - is built directly on top of the LED chip.
The Secondary Optic - collects and redistributes the light in the LED lamp.