How to Design a Simple LED Circuit

LED circuits are very easy to design. An LED or Light Emitting Diode, is a very low current light source that is very safe and durable for use in your project. This article will show you how to design and build a very simple LED circuit.

Things You'll Need

  • LED's
  • Resistor
  • Battery or power source
  • Wire or alligator clips
  • Helpful to have (multimeter)
  • Helpful to have (soldering iron)


    • 1
      Select the number of LED's you want in your project

      The first step is to choose how many LED's you want to light and their type (color, brightness). With this simple circuit you will be somewhat limited by the amount of voltage that can be safely provided for your project.

    • 2

      Calculate the amount of voltage you need from your power supply.

      Look for the "diode forward voltage" specification from the manufacture's website or packaging. If you do not have this information you can use the following to estimate:

      Red or Orange 2.0 V
      Yellow 2.1 V
      Green 2.2 V
      True Green, Blue, White 3.3 V
      Blue (430 nm) 4.6 V

      Say you want to have 3 Red LED's in your circuit. Only use the diode forward voltage value. So, 3 x 2.0 = 6V, needed.

    • 3
      Easy way to get 9 volts

      Once you have the required voltage, choose how you want to power the circuit. Do you want to plug it into an outlet and not have to change batteries or do you want the freedom to move around?

      DC voltage works easiest. AA, AAA, or 9V batteries are cheap and easy to find for a simple project. The simplest way to use AC as your source is a wall plug (wall wart), the large black plugs that come with most every electronic device you purchase. You probably have a box full of these sitting around. You will have to cut the plug off the end of the cord. Use a multimeter to determine the positive and negative lead.

      AC voltage can also be designed in the circuit. AC will only drive the LED half of the time since the voltage travels in waves. A full-wave bridge rectifier can be used to fully power LED's. This is essentially what the wall wart is doing for you.

      Find a power supply greater than the calculated diode forward voltage value from step 2. In our case we calculated 6 volts. A power supply value greater than 6 volts will be needed. If you are driving a large number of LED's, current may also be important.

    • 4

      Calculate the required LED resistor value.

      LED's cannot be connected directly to the battery or power supply. The LED will be instantly destroyed because the current is too great. The current must be reduced. The easiest way to do this is by using a resistor. Calculate the LED resistor value with the following formula:

      LED Resistor Value, R=(supply voltage - LED voltage) / LED current

      In our example:

      Say we use a 9V battery, then supply voltage = 9V.
      LED voltage for red LED's, from Step 2 is 2.0 V
      LED current is 20 mA (this is a typical value if not provided by the manufacturer)

      If the resistor value is not available, then choose the nearest standard resistor value which is greater. If you want to increase the battery life you can select a higher resistor value to reduce current. The reduced current will result in a dimmer LED.

      R = (9 - 2.0) / 20 mA = 350 ohms, use the next higher standard value = 360 ohms

    • 5
      You can keep your project organized by using a small PCB available at Radio Shack

      Wire your circuit together.

      You can soldier the wires directly together, use crimp connectors, or use a small circuit board. Choose the best method based on the size of your project.

    • 6

      The final step is to mount the LED's in your project. Radio Shack and others sell chrome or plastic LED holders that make a professional looking mount easy. You can add momentary push buttons or on/off switches to your LED circuits.

      Designing and building a simple LED circuit is an easy project.

Tips & Warnings

  • The longer lead on the LED is the positive side. Do not reverse the leads on the LED.
  • Remember that if you do not have the right resistor value handy you can put more than 1 resistor in series and add their values to get total resistance.
  • Make sure if you using AC with a full-wave rectifier to consider the voltage drop. Measure the output with a multimeter to be sure.
  • Never connect the LED's in parallel
  • Always use caution when working with power sources and soldering iron. They can be dangerous.
Related Searches


  • Photo Credit lifeengineer

You May Also Like

  • How to Design an LED Light Circuit

    Designing an LED light circuit is an excellent beginners electronics project and an easy way to decorate for the holidays. LEDs are...

  • How to Design an LED PCB

    Printed circuit boards are thin boards with patterns of micron-size wires and electrical components such as resistors and capacitors. Manufacturers design them...

  • LED Circuit Projects

    Light Emitting Diode (LED) circuits can be created with only a few simple components and can produce brilliant light in any color...

  • How to Build Sequential Flashing LED Circuits

    It's relatively easy to make a row of LEDs flash in sequence using simple digital electronics. Don't be scared by the word...

  • How to Build Simple LED Lights

    How to Design a Simple LED Circuit; How to Build an LED Light; Print this article; Things You'll Need. Two LEDs; 1k...

  • Simple Electronic Projects for Kids

    How to Design a Simple LED Circuit; Simple Electronics Mini Projects; Beginner Electronics Projects; Comments You May Also Like. Free Electronic Projects...

  • How to Make Flashing LED Circuit Board

    For a sample of LED flashing circuit design, see Resources below. 2. Print your design using a laserjet printer. Use a photo...

  • LED Flasher Circuit Projects

    An LED ("Light Emitting Diode") is a semiconductor that glows when current passes through it. As a diode, it only allows current...

  • Projects for Electrical Circuits

    LED Circuit Projects. Light Emitting Diode (LED) circuits can be created with only a few simple components and can produce brilliant light...

  • Electricity Science Projects on Circuits

    Easy Electric Science Projects on Circuits; Science Projects Using an Electric Circuit; Comments You May Also Like. ... An LED or Light...

  • How to Complete a Circuit With a 9V Battery

    How to Complete a Circuit With a 9V Battery. Electrical circuits need a power source. ... Making a simple circuit is ......

  • How to Wire an LED Light to a 9V Jack

    Calculate the size of the resistor you'll need in your circuit. If you don't have a resistor in the circuit the LED...

  • How to Design an LED/IR Lamp Flasher Circuit

    (Reference 1) You can easily put an LED flasher together with a 555 integrated circuit (IC) timer and a few outboard parts....

  • How to Build an LED Light

    Building a simple LED light can be a great project for kids or adults just learning electronics. An LED light can be...

  • How to Build a Simple LED Flashlight

    The incandescent bulb found in most flashlights does not provide a light as bright as a comparably-sized LED bulb. You can build...

  • How to Build a Circuit for Multiple LEDs

    As long as you know the values of your LEDs, putting together a circuit for multiple ones is fairly straight-forward. Simply calculate...

  • How to Make a Simple Light Circuit Project

    How to Make a Simple Light Circuit Project. ... How to Design a Simple LED Circuit. How to Make a Simple Circuit...

  • Circuit Design Projects

    Simple circuit design projects will give you the basics. Are you preparing for a career in electronics engineering or information technology? Are...

  • LED Lighting Projects

    Light Emitting Diodes, or LEDs, are used in a number of technological applications in 2010. Screens for appliances from laptop computers to...

  • DIY LED Kits

    How to Design a Simple LED Circuit; DIY LED Lighting; Print this article; Benefits. LED kits for beginners include blinking lights and...

Related Ads

Check It Out

Prep for Black Friday Checklist [Infographic]