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Tut1 Breadboard Circuits
Tutorial 1: Building a Circuit on Breadboard
Created on: 27 July 2012
Updated on: 12 January 2023
How to use a breadboard for beginners in electronics. This tutorial shows you how to build a very simple circuit on a breadboard that lights up a single Light Emitting Diode (LED). Building a circuit on breadboard is an essential skill for beginners in electronics to learn.
You will learn:
- About resistors
- About LEDs
- How to read a circuit diagram
- How to build a circuit on breadboard
Prerequisites to Building 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. Also read the five articles that follow the Start Electronics Now article, as can be seen near the top of the menu at the right of this page.
Components Used in this Tutorial
Learn about batteries, resistors and LEDs before starting this tutorial. Resistor values are color coded on the body of each resistor. See the basic information on resistors that shows how to read a resistor value.
Reading Resistor Values
If you have trouble reading a resistor, or just want to check that you read the correct value, then a multimeter set to the Ohms (Ω) setting is helpful. To measure the resistance of a resistor using a multimeter, first turn the multimeter dial to the Ohms setting. Afterwards, put the probe tip of one of the multimeter leads on one of the resistor leads. Finally put the other multimeter lead tip on the other resistor lead. Look at the display of the multimeter to see the resistance of the resistor being tested.
Note that a 5% tolerance resistor can have a value that is up to 5% above or 5% below its specified value. The resistance of a resistor measured on a multimeter will seldom be the exact value that the resistor color code specifies. This is because of the resistance tolerance margin. Common resistor tolerance values are 5% and 1%. These tolerance values come about because of the manufacturing process of the resistor.
Simple Breadboard Circuit Components
The following electronic components are needed to build the simple breadboard circuit.
| 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 colored and sized LEDs could also be used, e.g. 3mm green LED | Semiconductors |
You will also need:
- A breadboard
- Breadboard wire links
- 9V battery (nine volt battery)
- Battery clip
Reading the Circuit Diagram
The circuit diagram (also known as a schematic diagram) is shown below:
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 is instead represented by text that shows what voltage must be connected across the circuit. This diagram shows the alternate circuit:
Building the Circuit on a Breadboard
Before starting to assemble the circuit on the electronic breadboard, get the parts and tools ready. That is, get a battery clip, LED, 1k or 1000Ω resistor, wire link and breadboard ready.
This video clip shows what you will be doing – step by step instructions follow:
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 below. See the beginner's article on LEDs that explains how to identify the anode and cathode of an LED.
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 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 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 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.
How the Breadboard and Circuit Work
After building a breadboard circuit for beginners for the first time, it is important to know how the breadboard and basic circuit work.
Below is an explanation of how a breadboard is connected internally, including how the internal connections are insulated from each other. An explanation of the LED breadboard circuit connections for this tutorial follows.
Internal Breadboard Connections
Red lines in the photo below show how a breadboard is connected internally. The figure shows only some of the vertical connections, they repeat as shown.
Top and bottom parts of the breadboard are identical and have four horizontal connecting strips each. 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.
Note that narrower full-size breadboards usually have continuous horizontal connecting strips as the following image shows. Whereas the breadboard shown above has split horizontal rails. This means that the top and bottom of narrow breadboards only have two horizontal connecting strips each.
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.
LED Circuit Breadboard Connections
This photo shows the circuit built in this tutorial with the connecting strips of the breadboard that are used by the circuit in blue.
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.
Breadboard Circuit Frequently Asked Questions (FAQ)
- Q: The position of the LED in the circuit diagram is different from the breadboard circuit. Does this make a difference?
- A: The circuit in this example is a series circuit – the resistor and LED are connected in series rather than in parallel. It does not matter whether the LED and resistor are swapped. What does matter is that the LED is connected the correct way around so that current flows into the anode.
- What is the purpose of the resistor in the circuit?
- A: The purpose of the resistor is to limit the current flowing through the LED so that the LED is not burned out. Limiting the current also limits the brightness of the LED.
- Q: How do you choose the correct resistor for the circuit?
- A: First subtract the LED forward voltage from the battery voltage. Different colored LEDs have different forward voltages, so check the LED datasheet for this value. If the LED forward voltage is 1.7V and the battery is 9V, we subtract 1.7 from 9: 9 – 1.7 = 7.3V. Now decide how much current must flow through the LED, for example 10mA (ten milliamps, which is 0.01A). Divide the calculated voltage by the desired LED current. 7.3 ÷ 0.01 = 730Ω. Choose a resistor value that is close to the calculated value.