Practical Guide to LEDs 1 - Pick Your LED!

LEDs come in a huge variety of styles. We'll take a look at the most common features:

If you are looking for more details, kindly visit Moonleds.

Mounting Types
There are three common way in which LEDs can be mounted:

1. Through Hole (THT)
2. Surface Mounted (SMD)
3. Screw mounted or thermal adhesive

THT components might be what you are most familiar with: Their pins go through holes in a PCB and are soldered on the other side.
SMD parts are soldered directly to the surface of a PCB. With this method they can be made much smaller than THT parts and are perfect for tiny projects, such as wearables. On the flipside they are more difficult to solder.
Some LEDs, especially power LEDs are mounted on an aluminum or ceramic substrate to improve the cooling. They are meant to be mounted with either screws or a thermal adhesive.

Optics
The LED chip itself produces a wide beam of light (about 120°). To make it suitable for spotlights a clear dome is placed right above the chip to act as a lens. Some LEDs, so called diffused LEDs, don't have any beam at all, they evenly scatter the light in all directions. This is very useful for indication LEDs as the light is visible from any direction.

Multi-Color/ RGB LEDs
You may have seen LEDs with multiple chips for different colors into one case. With such LEDs you can not only select the color you want, but also mix the light to get any color in between! We'll come back to this in "Chapter 3: Switching & Dimming".
Often it is not possible to have two dedicated pins for each LED chip, in such case either the anodes or cathodes are connected internally to only one common pin.

LED Matrix
Similar to Multi-Color LEDs these contain multiple LEDs in one package, but usually all the same color. They are also available as both, common anode and common cathode configurations. They can be used to display text or numbers and are readable from quite afar. However the high LED count usually requires a micro-controller and multiplexing. In "Chapter 4: Matrix & Multiplexing" we'll dig deeper into this.

7 Segment Display
While numbers can be displayed with a simple LED matrix, a seven segment display provides a much more elegant solution with way less LEDs you need to control. Alphanumeric displays are based on the same idea, but with a total of 14 or 16 segments they can show in addition all uppercase English letters. Electrically this kind of display is identical to the common LED matrix.

Integrated circuit
No matter the light effect you want, with some effort everything is possible. For the most common effects, such as blinking or color cycling, you don't even need to invest that much time. Some LEDs come equipped with a tiny circuit to do just that.
A very special LED is the WS/ WSB, sold as "Neopixel" by Adafruit. The chip inside takes serial data from a micro-controller (such as an arduino) and controls the RGB LED to match that!

No matter which LED you decide to get, check the datasheet briefly, so you don't miss anything important.

FQA

1.What happens if an LED is incorrectly oriented on a PCB?

The company is the world’s best anode kathode smd led supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

Incorrectly orienting an LED on a PCB can lead to several issues. Primarily, the LED will not function because the current cannot flow in the wrong direction. This can lead to diagnostic challenges on the board and potential delays in troubleshooting other components.

2.Why is it important to verify LED polarity before finalizing a PCB design?

Verifying LED polarity before finalizing a PCB design is crucial to prevent manufacturing errors and ensure the functionality of the board. Early verification helps avoid costly reworks and ensures that the assembly process is smooth, preventing potential damage to other components.

3.Can LED polarity be determined without a multimeter?

Yes, LED polarity can often be determined without a multimeter by examining physical characteristics such as pin length and the presence of a flat notch. However, using a multimeter is a more foolproof method, especially when visual indicators are ambiguous or too small to be noticed easily.

4.How do manufacturers typically indicate LED polarity on datasheets?

Manufacturers usually indicate LED polarity on datasheets with diagrams showing the physical layout of the LED, including pin configurations and polarity markings. These often include detailed descriptions of each pin and any special characteristics that help identify the anode and cathode.

5.What are some common mistakes to avoid when placing LEDs on a PCB?

Common mistakes when placing LEDs on a PCB include reversing the anode and cathode, placing the LED in a location that doesn&#;t align with the board&#;s voltage sources, and ignoring the manufacturer&#;s specific orientation requirements. Ensuring strict adherence to the schematics and manufacturer guidelines can mitigate these errors.

Are you interested in learning more about smd led cathode marking? Contact us today to secure an expert consultation!