How to Build a Single LED Circuit

For this tutorial, I will be guiding you as to how a simple circuit is made. This simple circuit involves using a single LED (light-emitting diode) light along with some other components you will need to help light up that LED. The image on the right is a smiling face that is made up of many LEDs. That would be something that someone who is more proficient in the arts of circuitry would make. However, before you jump right into something that complex, you need to start somewhere simple. The left image represents what you will be able to make by the end of this tutorial.

LED: Before you even think about making an LED circuit, you must have all of the components that you need. One of the main components that you need, also the star of your circuit, is the LED itself. This LED can be any color that you want, whether it be green, blue, white, red, etc. The LED you use should be small in size and have two metal legs, one being longer and the other being shorter. The longer leg is called the anode (the positive leg) and cathode (the negative leg).

A 9V Battery: An essential component that is needed for completing your LED circuit is a 9V (V=Volt) battery such as the one presented above. The shape if it is a rectangular prism with two connectors at the top. There should be a clear label on the battery itself with what the voltage is. If there isn't one or you are not sure, use another battery that is more clear in displaying its qualities. The two connectors at the top are used to help distribute the power to the rest of the circuit.

Battery Cap: The battery cap is put on top of the 9V battery by latching itself onto it using the metal components. If you didn't understand, think of it as a seatbelt buckle and the seatbelt itself being put together. The battery cap should have two cables running out of it; one red and one black (refer to the image above that is next to the image of the battery). The red cable is also known as the power cable and the black cable is also known as the ground cable. Remember that for later in the tutorial.

Breadboard: The breadboard is used for prototyping electronics and circuits. You are able to use an array of components besides the ones listed here to make any kind of circuit. The use of the breadboard for this tutorial, however, is to help direct the flow of electricity so the LED can be lit up.

Resistor: You will need a resistor for this circuit because, without one, the flow of electricity will just flow through the circuit without any kind of control. As a result, the circuit could generate heat and, depending on the size and intensity of the circuit you make, could also catch fire or explode. The unit of measure for resistance is in Ohms (Ω). To measure the amount of resistance a single resistor has, you need to look at the colored bands on it. There are calculators on the internet that are able to determine the amount of resistance you are working with so you don't mix them up or use too little or too much resistance. My favorite website is this one here. So, the amount of resistance needed for a 9V battery would be around 350 Ohms. There is most likely not a resistor that has that exact number of Ohms you are looking for, so you are able to choose one that has relatively more or less resistance.

For this step, you will want to grab your battery cap and your 9V battery. You will then put the battery cap on top of the battery, making sure the connectors correspond with each other in size. Sometimes putting on the battery cap will require a bit of strength. Despite the slight difficulty of putting the cap on, that should be the final part of this step. The more strength that is applied to putting the cap on the battery usually indicates that it should be rather difficult to separate them as well.

For this step, you will need the assembled battery, the breadboard, the resistor, and the LED. The picture above shows you where everything goes according to colored circles.

Just a disclaimer, the columns that have the letters are not significant. Meaning the placement of which row or which column you want to put the component into does not matter. However, the columns with the red plus sign and the blue negative sign are more important when regarding the placement of components. The rows labeled by number don't matter, but where the component is placed in the column is important because these are based upon the polarity of the components used. I placed these circles the way I did because it is easy, convenient, and efficient for me personally.

The red circle represents the red wire (power) coming from the battery cap, the black circle represents the black wire (ground) coming from the wire.

The blue circles indicate where the two sides of the resistor go. Whether you put one side of the resistor in one side or the other doesn't matter as the resistor does its job regardless or placement.

Finally, the green circles represent where the two legs of the LED are going to be placed. Placement does matter with the LED, as there are two different polarities or charges on each leg. The longer leg called the anode (positive charge) goes in the green hole next to the blue resistor hole to the left as indicated by the image above. The shorter leg called the cathode (negative charge) goes inside the green circled hole that is right next to where the ground wire, or the black circle, is placed.

If you have completed all steps up to this point, you are finished with the single LED circuit and should have a bright and glowing light in front of you!! Amazing Job!! If you have any questions regarding any of the steps, please don't hesitate to ask in the question/comment section. I will answer them to the best of my ability.