Ttronic

LED Series Resistance • The series resistor value RS is calculated by simply using Ohm´s Law, by knowing the required forward current IF of the LED, the supply voltage VS across the combination and the expected forward voltage drop of the LED, VF at the required current level, the current limiting resistor is calculated as:

Types of Light Emitting Diode  • Gallium Arsenide (GaAs) – infra-red • Gallium Arsenide Phosphide (GaAsP) – red to infra-red, orange • Aluminium Gallium Arsenide Phosphide (AlGaAsP) – high-brightness red, orange-red, orange, and yellow  • Gallium Phosphide (GaP) – red, yellow and green  • Aluminium Gallium Phosphide (AlGaP) – green  • Gallium Nitride (GaN) – green, emerald green  • Gallium Indium Nitride (GaInN) – near ultraviolet, bluish-green and blue  • Silicon Carbide (SiC) – blue as a substrate  • Zinc Selenide (ZnSe) – blue  • Aluminium Gallium Nitride (AlGaN) – ultraviolet Light Emitting Diodes I-V Characteristics.

Light Emitting Diode Colours  • So how does a light emitting diode get its colour. Unlike normal signal diodes which are made for detection or power rectification, and which are made from either Germanium or Silicon semiconductor materials, Light Emitting Diodes are made from exotic semiconductor compounds such as Gallium Arsenide (GaAs), Gallium Phosphide (GaP), Gallium Arsenide Phosphide (GaAsP), Silicon Carbide (SiC) or Gallium Indium Nitride (GaInN) all mixed together at different ratios to produce a distinct wavelength of colour.

Light Emitting Diode The “Light Emitting Diode” or LED as it is more commonly called, is basically just a specialised type of diode as they have very similar electrical characteristics to a PN junction diode. This means that an LED will pass current in its forward direction but block the flow of current in the reverse direction. • Light emitting diodes are made from a very thin layer of fairly heavily doped semiconductor material and depending on the semiconductor material used and the amount of doping, when forward biased an LED will emit a coloured light at a particular spectral wavelength. • When the diode is forward biased, electrons from the semiconductors conduction band recombine with holes from the valence band releasing sufficient energy to produce photons which emit a monochromatic (single colour) of light. Because of this thin layer a reasonable number of these photons can leave the junction and radiate away producing a coloured light output. • Also, nearly al...

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Single Sided or Single Layer Types of PCB •Single Sided PCB is the simplest low cost PCB or printed circuit board. These types of PCB has only one single layer of the base    substrate (Fiberglass) and one single conductive (copper) layer. Holes for electronic components are generally not plated through. Layout for the electronic components is on one side and the conductive circuit is on the other side. Since, there is only conductive layer forming the circuit, it is called single sided PCB or One Layer PCB or Single Layer PCB.

Different Types of PCB •Single Sided PCB or Single Layer PCB  •Double Sided PCB or Double Layer PCB  •Multilayer PCB  •Rigid PCB  •Flex PCB or Flexible PCB  •Rigid-Flex PCB or Rigid-Flexible PCB

printed circuit board                    A printed circuit board or PCB, is a plate or board used for placing the different elements that conform an electrical circuit that contains the electrical interconnections between them.                     The most simple printed circuit boards are the ones that contains copper tracks or interconnects only on one of its surfaces. These kinds of boards are known as 1 layer printed circuit board or 1 layer PCB.                                    The most common PCB's manufactured today are the ones that contain 2 layers, that is, you can find interconnects in both surfaces of the board. However, depending on the physical complexity of the design ( PCB layout ), the boa...