Starting Electronics needs your help! Please make a donation to help cover our hosting and other costs. Click the donate button to send a donation of any amount.

Tutorial 1: Building a Circuit on Breadboard

Created on: 27 July 2012

This tutorial shows you how to build a very simple circuit which lights up a single Light Emitting Diode (LED).

You will learn:

  • About resistors
  • About LEDs
  • How to read a circuit diagram
  • How to build a circuit on breadboard


You need to know about tools and electronic components before starting this tutorial - if you haven't read the Start Electronics Now! article, then read it now.

Learn about batteries, resistors and LEDs before starting this tutorial.


Qty Part Designator Notes Type
1 1k resistor (1000 ohm, brown - black - red) R1 1/4W, 5% or better Resistors
1 5mm red LED D1 Other coloured and sized LEDs could also be used, e.g. 3mm green LED Semiconductors

You will also need:

  1. A breadboard
  2. Breadboard wire links
  3. 9V battery (nine volt battery)
  4. Battery clip
Components needed for the tutorial: battery clip, LED, resistor and wire link
Battery Clip, LED, Resistor and Wire Link

Books that may interest you:

C Programming with Arduino Book Ultimate Arduino MEGA 2560 Hardware Manual Ultimage Arduino Uno Hardware Manual

Reading the Circuit Diagram

The circuit diagram (also known as a schematic diagram) is shown below:

LED circuit diagram
LED Circuit Diagram

This circuit diagram tells us (clockwise from the battery): Connect the positive terminal of the battery (red battery clip lead) to the 1 kilo-ohm resistor. Connect the other lead of the resistor to the anode of the LED. Connect the cathode of the LED to the negative terminal of the battery (black battery clip lead).

Often the battery or power source is not shown in the circuit diagram. It will be represented by text that will show what voltage must be connected across the circuit. This diagram shows the alternate circuit:

Alternate circuit diagram
Alternate Circuit Diagram

Building the Circuit

Get the parts and tools ready:

Step 0: Parts and tools needed to build the circuit
Parts and Tools for the LED Breadboard Circuit

This video clip will show you what you will be doing – step by step instructions follow:

Can't see the video? View on YouTube →

Step 1: Insert the LED into the Breadboard

Start by bending the longer lead of the LED as shown in the previous photo. Plug the longer lead (anode) of the LED into the top rail of the breadboard and the other lead into a hole in the main part of the breadboard as shown:

Step 1: Insert the LED into the breadboard
Step 1: Insert the LED into the Breadboard

Step 2: Insert the Resistor into the Breadboard

Use the side cutters to remove a 1k resistor from the string of resistors if they are taped together. Cut the resistor lead as near to the tape as possible. Don't try to remove the tape as this will leave a sticky mess on the end of the resistor lead which will then end up in your breadboard.

Bend the leads of the resistor as shown below. Plug one of the resistor leads into a hole directly below the cathode lead of the LED and the other lead into a hole below the middle channel of the breadboard. This connects the LED cathode to one of the resistor leads. It does not matter which way around the resistor is plugged into the breadboard.

Step 2: Insert the resistor into the breadboard
Step 2: Insert the 1kΩ Resistor into the Breadboard

Step 3: Insert the Wire Link into the Breadboard

Insert a wire connector into a hole directly below the resistor lead and into the bottom rail of the breadboard.

Step 3: Insert the wire link
Step 3: Insert the Wire Link

Step 4: Insert the Battery Clip into the Breadboard

Plug the red (positive) wire of the battery clip into the top rail of the breadboard. Plug the black (negative) wire of the battery clip into the bottom rail of the breadboard.

Step 4: Insert the battery clip
Step 4: Insert the Battery Clip into the Breadboard

Step 5: Plug the Battery into the Battery Clip

Finally plug the battery into the battery clip to power up the circuit and switch the LED on. Make sure to connect the battery clip to the battery the right way around. The opposite type of connector on the battery clip must be connected to the battery terminals, i.e. the battery and battery clip each have a pair of terminals and they will only connect to each other one way. If you try to connect them the wrong way, they won't clip together, but they will put reverse polarity on the circuit for a moment which may destroy the circuit, so be sure to connect the battery the right way around the first time.

Step 5: Connect the battery to the breadboard circuit
Step 5: Connect the Battery to the Breadboard Circuit

How the Breadboard and Circuit Works

The red lines in photo below show how the breadboard is connected internally. The figure shows only some of the vertical connections, they repeat as shown.

Breadboard internal connections
Internal Connections or Wiring of the Breadboard

The top and bottom parts of the breadboard are identical and have four horizontal connecting strips. The middle of the breadboard has vertical connecting strips separated by a horizontal channel in the middle.

Each individual red line or connecting strip is electrically isolated from every other strip.

Any component lead that is plugged into a hole or "tie point" of the breadboard will be connected to whatever is plugged into a hole of the same connecting strip as marked in red in the photo.

This photo shows the circuit built in this tutorial with the connecting strips of the breadboard that are used by the circuit in blue.

Current flow in the circuit
Current Flow in the LED Circuit

The red lead from the battery is joined to the LED via the top horizontal strip of the breadboard. The LED connects to the resistor using a top vertical strip. The resistor is not shorted out because it jumps across the middle insulated channel of the breadboard to a vertical connecting strip below. The wire link connects the bottom resistor lead to the bottom horizontal connecting strip which is then connected to the black lead of the battery.

I hope that you enjoyed this tutorial and found it useful. This tutorial was kept simple as an introduction to some basic electronic components and so that you can learn how a breadboard works before tackling more complex circuits.

As an Amazon Associate I earn from qualifying purchases: