What is the difference bertween SMD and PTH LEDs ?

SMD is the acronym of Surface Mounting Device and it is the new frontier of the electronic visualization technology: the revolution created by the SMD technology is represented by the miniaturization of all the electronic components, LEDs included. The SMD components are mounted on the surface of the electronic board, without passing through it as any other electronic component utilizing the former technology, called PHT (acronym of “Plating Through Holes”).
The SMD TOP LED is therefore mounted on the external part of the board (without the anode and cathode passing through holes), as described in the image below (proportions are real): LEDs utilizing the SMD technology are different from the PHT LEDs for another important characteristic: thanks to the miniaturization indeed it is possible to put 3 LEDs of different colors within the same case (as in the picture on the top-right), resulting in a three colors LED.
The possibility to visualize three colors at the same time (Red, Green and Blue) on a single LED allow to create digital billboards with an even smaller pitch (the distance between pixels) therefore resulting in a higher resolution and quality image.

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