SMD LED STRUCTURE AND DESIGN
SMD LEDs are rectangular in shape and consist of three cells. These cells contain a luminescent element (semiconductor crystal) that produces light when current flows through it.
To protect the SMD cells, resins are used to completely cover the upper part. These resins for SMD are available in various colors and shades.
Depending on the number of cells in the SMD led, it will have a certain number of contacts for welding. For a single-color LED, one of them is always the anode (+) and the other will be the cathode (-). In the case of an SMD RGB LED it usually has a cathode contact and an anode for each luminescent element. Depending on the manufacturer and the LED specification, the configuration and number of connection points can vary.
SMD LED SIZES
Depending on their size, LED types are classified with a 4-digit number: the first 2 digits for the length and the next 2 for the LED height in tenths of a millimeter. For example, a 5050 led is 5x5mm. The following table shows the most commonly used SMD LED types: