LED Starter Kit Retail

The LED Starter Kit includes LEDs, resistors, and a coin cell test battery to allow you to quickly and easily add light to any project. This guide will show you how to quickly get started using the kit, and give you a basic understanding of how to connect and power the LEDs. It is intended only to show on a basic level how to use your kit. For an in-depth guide on using LEDs see our LED Laden Bike Helmet Tutorial. For a basic description of LED physics, see our Anode vs. Cathode Bite-Size Primer. If you plan on working with LEDs more in the future, it is recommended that you read both of these documents.

Have a look at the contents of your kit. Some of the LEDs have two leads (wires coming out of them) and some of them have four. The LEDs with two leads are single color LEDs, and the LEDs with four leads are RGB LEDs. Let's look at both of them.

Single-Color LEDs

The single-color LEDs have two leads. You'll notice that you have red, green, and clear LEDs. But wait, doesn't the kit include six colors (Red, Orange, Yellow, Green, Blue, and Violet)? The answer is yes, but only the red and green LEDs have a cap that indicates color. The orange, yellow, blue, and violet LEDs have clear caps. This is where the coin cell battery comes in. To test the color of a clear LED, you can quickly connect the coin cell battery to the leads. The positive side of the coin cell battery is indicated by the “+” symbol on the side with the larger diameter.

To test the color of a clear single-color LED, insert the coin cell between the battery leads with the positive side of the battery contacting the longer lead on the LED.

The LED should light up, indicating it's color. If it does not, make sure that the battery is oriented correctly and that both sides of the battery are touching the LED leads. This battery is meant as a test only, and if left connected to the LED for too long (e.g. 24 hours), it will die, so make sure to not leave the battery connected for longer than it takes to perform a color test. Note: do not connect the LED to a larger power source without a resistor to test it's color. This may burn out the device. The coin cell battery delivers a low current that is too low to damage the device.

In order to connect the LED safely to a power supply that can deliver more current, the LED must be connected to a current-limiting resistor. As the name states, the resistor will only allow a safe amount of current to travel through the LED. Your kit comes with 25 330 Ohm resistors.

The reason that the resistor has a value of 330 Ohms is because this value allows safe use of all the LEDs with a 5 volt power source. Much more than 5 volts, and the resistor value will be insufficient to protect the LED. If you'd like to use the LEDs with a higher voltage source, please read the more in-depth LED-Laden Bike Helmet tutorial.

To use the single-color LEDs in your project, you'll need to connect one end of the resistor to the long lead of the LED. You can do this by soldering the leads together, or twisting them together. Soldering the leads together is recommended because it will allow for the most robust and quality connection. If you need to learn how to solder, have a look at our Soldering 101 tutorial. Once the two devices are connected. You can connect the other end of the resistor to the positive end of the power supply, and the other end (short lead) of the LED to the negative, or ground, end of the power supply. This is the basic connection of a single-color LED.


An RGB LED is very similar to a single-color LED, the only difference being that it can emit three colors in a single package. Imagine taking the “guts” of a red, green, and blue LED and putting them in a single assembly. The reason that there are four leads (instead of six) is that the LED is “common cathode” meaning there is only one pin that connects to ground. The longest lead of the device is the common cathode lead and the other three leads power the three separate colors. To see which lead corresponds to which color, refer to the diagram below (from page 2 of the RGB LED datasheet).

The RGB LED can also be tested with the coin cell battery, just like the single-color LED, it just takes a bit more maneuvering since there are four leads. Just make sure that the negative (not marked with “+” side of the battery is contacting the longest lead.

Just like the single-color LEDs, the three power leads of the RGB each require their own 330 Ohm resistor. Solder these resistors on and connect one, two, or three of the resistors to power, and the long lead of the LED to ground. Play with different combinations of power connections to get interesting mixed colors!

That's the basic way to connect the LEDs from your LED Starter Kit to your project. For more information on connecting multiple LEDs, using different voltages, and understanding LEDs and resistors on a schematic, be sure to read our LED Laden Bike Helmet Tutorial and LED Current Limiting Resistors Tutorial.

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