For it to work properly, the current must go from anode to cathode. Thus, an LED is polarized and will only emit light if it’s connected correctly. As mentioned, a diode will allow the current to flow in only one direction. Non-polarized components can be connected either way and they will work properly (e.g. In electronics, polarity indicates the symmetry of a component, meaning it will matter how you connect it if it’s polarized. To understand how to work with LEDs, we have to know some things about them. The color of the LED will depend on the compound used. The semiconductor die, the thing that makes LED emit light, is made from gallium arsenide (GaAs), gallium phosphide (GaP), gallium arsenide phosphide (GaAsP), silicon carbide (SiC), gallium indium nitride (GaInN), aluminum gallium indium phosphide (AlGaInP), and similar chemical compounds. A die is inside a little divot on the anvil, and the bond wire leaps from anvil to post, connecting the two.įor the light to be emitted, the diode has to be made from special material. The post is the positive side of the LED, the anode side, and the anvil is the negative side, the cathode. The inside of the LED consists of two main parts – post and anvil. This makes it more durable to fall or similar damage. The case or housing of the LED is usually made from epoxy or plastic material. If you take a closer look at an LED, you will see it’s made of several parts. They represent the light being emitted from the diode. The only difference between a diode and an LED in the schematic is the arrows added over the symbol. This similarity is reflected even in the schematic , as seen below. The only difference is that it emits light when the current passes through, as the name suggests. It allows current in only one direction and will stop it from flowing in the other. Note the pin length orientation clue.The first question that might pop into your mind is, what is exactly an LED? A regular diode is a semiconductor device that works as a one-way switch for electrical current. Kingbright LF5WAEMBGMBW, 6-pin, RB-GB LED has two 3-pin LEDs in one package. This package consists of a red-blue pair and a green-blue pair in one package. This allows a single part to be used for common anode, common cathode and series LED configurations.Ī slightly strange 6-pin, RB-GB, LED, has two separate 3-pin LEDs in one package. One sensible one is to bring out each LED anode and cathode on individual pins. When the number of pins reaches six all sorts of strange variations are possible. RGB with individual pinouts allows common anode, common cathode configuration as well as series connection of the LEDs. Common cathode and common anode versions are available. The 4-pin package is most commonly seen on RGB (red-greeen-blue) LEDs. 4-pin The popular RGB, 4-pin, LED allows generation of colours across the visible spectrum. Either LED can be turned on independently or blended to create a combination. The three-pin LED is usually a pair of LEDs of different colours sharing a common anode or common cathode. The bi-colour LED’s datasheet will specify which way round to connect to ensure the correct colour. Others may have both LEDs the same colour and this can be useful in AC applications as it can conduct on both cycles of the mains and eliminates the need for a rectifier. Some are dual-colour so that reversing the current through them changes the colour. The two-pin package can contain a single or two back-to back LEDs.īe aware that bi-colour LEDs are also sold in this package. Generally these are a single LED. Polarity is indicated by the long lead (+ / anode) or the flat on one side of the base (- / cathode). The most common type of LED is the 2-pin, 5 mm, round lens type. It helps during assembly as pins can be inserted one at a time from longest to shortest without having to align all the pins simultaneously. Note that LEDs usually have no two pins the same length. See Testing unknown LEDs for more on this topic. You can use a higher voltage such as a 9 V battery and double the value of R1 but you might damage sensitive devices on reverse voltage. A 5 V supply is available from a USB supply or, for example, an Arduino. Most LEDs will light at less than 5 V and can tolerate 5 V reverse voltage. Simple LED test circuit Simple LED test circuit. Most LEDs are simple single device with two leads but packages with two or more LEDs are common and there are various LED pinouts in use.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |