SMD LED means SMT light emitting diode which helps to improve the production efficiency and it can be used in various fields. SMD LED is a kind of solid state of the semiconductor device which can directly convert electric to light. SMD is the abbreviation of Surface Mounted Devices which means the Surface Mount Devices. SMD is one of the components of SMT (Surface Mount Technology). The 3528 SMD and 5050 SMD are two common types of SMD. SMD LED is made up of FPC board, LED lamp and high quality silicone casing. It has luminous color and waterproof performance which are convenient and safe supplied by low voltage dc power. Even using in the outdoor it has the advantages of resistance to UV aging, to become yellow and to high temperature. The products are widely used in the field of the building clearance lighting, places of entertainment decorative lighting, advertisement decoration lighting, etc. The voltage of SMD LED is 1.9-3.2V, and the voltage of the red SMD LED and the yellow SMD LED are lowest. The heart of LED is a semiconductor chip, one end of chip attached to a support which is negative, and the other end connected to the power of positive---that structure makes the entire semiconductor chip encapsulated up by epoxy resin.
The Common Types of SMD LED
3528 SMD and 5050 SMD LED are the two table stick types of light emitting diode (LED). 3528 in stand of appearance size which is 35 * 28 and 5050 means that its appearance size is 50 * 50. The luminous flux of 3528 SMD is about 3-9 lm and the luminous flux 5050 SMD is about 11-21 lm.
The Working Principle of SMD LED
Semiconductor chip consists of two parts. One part of it is a P-type semiconductor which is dominant in the whole structure, and the other end is n-type semiconductor which is primarily electronic. But these two kinds of semiconductor link, they formed a p-n junction between them. When an electric current passes through the chip on the conductors, electronic will be pushed to the P area, in the P area electronic compound with hole, and then they will be issued in the in the form of photon energy which is the principle of LED lighting. And the wavelength of light, that is the color of the light, is determined by the formation of p-n junction material.
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