How to Build a Simple LED Light Circuit With a Battery and Switch


Building a simple circuit with an LED light, battery, and switch is a great way to learn the basics of electronics and circuitry. With just a few inexpensive components, you can make a fun DIY project in under an hour. In this article, I will walk you through the step-by-step process of assembling this basic but illuminating circuit.

What You Will Need

To build the LED light circuit, you will need the following components:

Calculate the Resistor Value

The resistor is a very important component of the LED circuit. It prevents too much current from flowing to the LED which can damage it. To determine the proper resistor value, you need to calculate it using Ohm's Law.

Here is the formula:

R = (V - Vf) / If


Look up your LED's Vf and If specs to plug into the equation. For example, for a standard red LED powered by a 9V battery, with If = 20mA (0.02A):

R = (9V - 1.8V) / 0.02A = 350Ω

So for this circuit, a 350Ω resistor would be ideal. The closest standard value is 330Ω.

Breadboard Assembly

With the components and resistor value figured out, it's time to assemble the circuit on the breadboard. Follow these steps:

  1. Insert the LED into the breadboard, with the long positive leg in row 15 and short negative leg in row 16.

  2. Place the resistor across rows 13 and 15.

  3. Insert the battery holder or 9V snap connector across rows 1 (negative) and 2 (positive).

  4. Use a jumper wire to connect row 1 to the negative LED leg at row 16.

  5. Install the switch across rows 2 and 14.

  6. Connect row 14 to the resistor on row 15 with another jumper. This completes the circuit.

Refer to the diagram below for visual guidance:

How to Build a Simple LED Light Circuit With a Battery and Switch

Test and Troubleshoot the Circuit

Once assembled, install a battery into the holder and flip the switch to test it out. The LED should light up!

If it does not, go over these troubleshooting tips:

With attention to detail, you should be able to get the simple LED circuit working. It's an easy and educational electronics project. Have fun lighting it up!

Example Projects

Here are some example projects you can build using this basic LED light circuit:

Blinking LED

Add a transistor, capacitor, and 555 timer chip to make the LED blink on and off repeatedly. This teaches oscillator circuit design.

Color Mixing

Use RGB LEDs and adjust the resistor values to blend different colors of light. Learn how color is produced.

Mini Flashlight

Mount the LED on a small enclosure with the battery and switch. Handy for power outages or as an ornament.

LED Throwies

Stick a magnet and LEDs with batteries onto small felt pads. Toss them onto metal surfaces for creative lights displays. Fun project!


Constructing a simple battery-powered LED circuit with a switch is a great DIY project to understand how circuits work. Determine the correct resistor value, assemble the components neatly on a breadboard, troubleshoot any issues, and enjoy lighting up your LED successfully. Use this knowledge to create more complex blinking and color mixing circuits. The possibilities are bright!