There is no standard mains voltage and frequency throughout the world. Also plug shapes, plug holes, plug sizes and sockets are also different.
When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon (light).
Why we should use LED's products?
LEDs were first developed in the 1960s but were used only in indicator applications until recently.
LED is a kind of electronic parts and components.
LED is stand for light-emitting-diode.
FAQ for LED,LED lighting,LED Lamp
HS Code of LED Lights for customs clearance.
COB technology allows the LED modules to be clusters on the circuit boards. Chips are mounted directly on to the circuit board.
Compare to SMD, High Power LED, Super Flux LED and through hole LED,There is some advantage of COB.