LED project

LED Project

LED stands for Light Emitting Diode. What is a diode, you ask? A diode is a device that allows for electricity to flow one way but not the other. We'll get to why that's important a little later.

The LED light is a simple, efficient light source that is showing up everywhere. LEDs not only make our world brighter, they are also the way that many electronic devices and robots “talk” to us. Some example are:

  1. Your computer's "on" light. That light is an LED!
  2. Find your favorite toy. If it blinks, the thing blinking is an LED!
  3. Many cars have headlights that turn on during the day. Many of these are LEDs because of their long lifespans and efficiency.

Can you find more examples in your home or at school? Post them in the comments section.

--- Click on the image for animated assembly instructions ---

LED circuit assembly using mini breadboard

Today we will build our first LED circuit.

LED circuit schematic diagram

The learning concepts to master are:

Electricity has 2 types of charge + positive and - negative. It matters which direction components are connected.

All electrical circuits must make a complete loop from the + positive side of the power source to the - negative side. There can be no breaks in this loop or it will not work.

Remember when we said a diode is a device that allows electricity to flow one way but not the other? Well, this is why an LED needs to connected properly. If not, then the electricity can flow in the wrong direction, creating a break in the circuit. And when that happens, the light can't turn on. This is why it is important to know how your LED is connected.

How does a light switch work?

Let me ask you a question. Have you ever wondered how does a light switch work? How does flipping a switch on one end of the room, turn a light on at the other end?

Well, now that you know how circuits work, the answer is very simple. A switch is a circuit component that is used to "break" the loop to turn a circuit off. Likewise, a switch can also "close" a loop, and turn the circuit on. On, off. Get it? Pretty neat, huh?


A resistor is a circuit component that is used to control, or "resist," the flow of electricity through the loop. This is important because it keeps a circuit from burning out. What good is an LED that doesn't light up anymore, right?

Why is my LED red?

The color of an LED is determined by the characteristics of the electronic device, not the color of the plastic. Specifically, it depends on the kinds of materials, called semiconductors, that are used to make the LED.

Check out this list to see what kinds of semiconductors make certain colors of lights.

LEDs Everywhere

Some of the most amazing displays of LEDs were at the Beijing Olympics in 2008. Check out some here. Believe it or not it is the same little circuit that you made here, just lots more of them and lots more detail.


First, look at the Battery Review and Quiz and then head over to the LED Quiz. Hopefully you'll be able to point out LED lights around your house and you'll start seeing electrical circuits in various places, if you look for them!

STEM Education Standards

  • STEM Science StandardElectrical Energy
    Students will recognize that electricity has two types of charge positive and negative and circuits require a complete loop from + positive source to - negative.
  • STEM Engineering StandardElectrical Components
    Students will be able to identify components, symbols and explain the function of LED, Resistor, Switch and Battery