Lesson-11 How to use a Breadboard
An electronic breadboard simply refers to a solderless breadboard or you can also call it a circuit builder. Breadboards are one of the most fundamental electronic components required by beginner student engineers when learning how to build circuits. Breadboards are a great choice for building temporary circuits, testing out new components such as ICs and prototyping since they require no soldering and can be re-used over and over countless times.
Have a look at the previous tutorials;
Lesson – 07: Series and Parallel Circuits
Lesson – 08: How to use a Multimeter
Lesson – 09: Buttons and Switch Basics
Lesson – 10: Battery Technologies
In this tutorial, we’ll learn about what breadboards are, why they are called breadboards, how they work and how we use them to build basic electronic circuits.
The beauty about breadboards is that they can house both the simplest circuits and very complex circuits since they can be combined to accommodate circuits of all sizes and complexities.
Breadboards are called breadboards because originally, people used their kitchen polished pieces of wood that were used for slicing bread (kitchen bread boards) for prototyping their electronics circuits and the name stuck till today.
The anatomy of a Breadboard;
For us to better understand how a breadboard works, we need to look at it part by part.
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Power Rails;
These give you lots of easy access to power whenever you need it on your circuit. Breadboards usually have two stripes (Red and Blue/Black) labelled with a “+” and a “-” on both sides of the board to indicate the positive and negative side.
It should be noted however, that the two power rails on either side are not connected to each other and if you need the same power source on both sides, you’ll need to connect the two sides with jumper wires as shown below;
Please ensure you always attach the “+” to “+” and the “-” to “-” as shown above.
It should also be noted that the markings on the power rails are meant for reference purposes to keep everything in order while you’re prototyping.
While working with larger breadboards, you should be aware that some large breadboards will often isolate one half of the breadboard’s power rails from the other half. This comes in handy if you have two different voltages powering your circuit such as 3.3V at one end and 5V at the other end.
It’s always a good idea to use a multimeter to check for the absence or presence of continuity in your breadboard’s power rails in case you’re unaware whether the power rails are or aren’t isolated which can lead to issues while working on your circuits.
Power can be supplied to the breadboard power rails by borrowing power from other development boards such as an Arduino/Raspberry Pi. The Arduino/Raspberry Pi have multiple power and ground pins that you can connect to the power rails or other rows on a breadboard as shown below.
The Arduino/Raspberry Pi usually get their power from the USB port on a computer or an external power supply such as a battery pack or a wall outlet charger.
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Binding Posts;
Some breadboards come on a platform that has binding posts attached to it. These posts are used to connect all kinds of different power sources to your breadboard.
There are different ways in which we can provide power to the breadboard and one of them is through the binding posts. It should be noted that although the posts are connected to the breadboard, they are not electrically connected.
To connect the posts to the breadboard, we must use jumper wires and this is done by unscrewing the posts (red and black) until the holes going through are exposed, then slide the stripped end of the jumper wire through the holes and screw the posts back down until the wires are firmly connected. Then connect the other ends of the jumper wires on to the breadboard. By doing this, the posts are connected to the breadboard but there is no power supplied to it yet.
Other methods of providing power to the Breadboard;
There are different ways of providing power;
a). Benchtop power supplies;
These allow you to provide a wide range of voltage and current to your circuit and using a pair of banana connectors, you can provide power from the power supply to the binding posts.
b). Barrel jack;
You can also solder a barrel jack to some wires and then connect them to them to the binding posts. If the breadboard you’re using doesn’t have binding posts, you could just plug the wires from the barrel jack directly in to the power rails of the breadboard.
c). Breadboard power supplies;
The other simple method of providing power to your breadboard is to use one of the many breadboard power supplies available. Some of these power supplies pull power from your computer’s USB ports and they also have the option to choose between 3.3V and 5V
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Terminal Strips;
Almost all breadboards have these terminal strips composed of five clips that are electrically connected horizontally on either side separated by a ravine/valley in the middle. The ravine in the middle isolates both sides of a given row from one another and the two sides are not electrically connected which leaves five spots for connecting components on either side of the board.
When we remove the adhesive backing off the back of the breadboard, we see lots of horizontal rows of metal strips on the bottom of the board. The top of the metal rows has little clips that hide under the plastic holes where each metal strip and socket is spaced with a standard pitch of o.1” (2.54mm).
These clips allow you to stick a wire or the leg of a component into the exposed holes on a breadboard which then hold it in place and once inserted, that component will be electrically connected to anything else placed in that row. This is simply because the metal rows are conductive and they allow current to flow from any point in that strip.
Rows and Columns;
When you look closely on your breadboard, you’ll notice there are numbers (from 1-30 or 1-60) and letters (from a-j) marked on the various Rows and Columns respectively. These are used to help guide you when building your circuit so that your circuit doesn’t malfunction in case of a misplaced leg of a component.
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DIP Support;
The ravine/valley that separates the two sides of the breadboard was specifically incorporated into breadboards to serve a very important purpose of connecting large components such as Integrated Circuits (ICs). These usually come in what is known as a Dual in-line Package (DIP) design – (a design where the legs come out of both sides of the component to fit perfectly over the valley) in order to minimize the amount of space they take up on the breadboard as shown below.
All ICs have legs that are unique and when using an IC we don’t want both sides to be connected to each other and this is where the separation in the middle of the breadboard comes in handy to help us connect components on both sides of the IC without interfering with the functionality of the leg(s) on the opposite side.
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Slots and Nubbins;
These are little dents and protrudings on the sides and even on the tops and bottoms of almost every breadboard. These allow you to connect multiple breadboards together to form the ultimate prototyping surface that you require for your project in case the circuit requires a lot more space.
Other features;
Some breadboards do come with an Adhesive backing that allows you to stick them to many different surfaces and this comes in handy if you want to attach your breadboard to the inside of an enclosure or any project casing that you might be working with.
Building our first Breadboard Circuit;
Having looked at the internal and external structure of a breadboard and how we can provide power to it in various ways, we can go ahead and build our first simple circuit.
Here’s what you’ll need;
- 1x breadboard
- 1x 330Ω Resistor
- 1x Momentary push-button switch
- Jumper wires
- 1x LED
- 1x Wall adapter – 5VDC
- 1x Breadboard power supply
Connect your circuit as shown in the schematic below. Feel free to change the orientation of the design provided everything is connected as it’s supposed to be.
In the Circuit above, we have a wire connecting the Vcc power rail to the positive (anode) leg of the LED, the negative (cathode) leg of the LED is connected to the 330Ω resistor, the resistor is then connected to a push-button. When the push button is pushed, it connects the circuit to ground completing the circuit and turning on the LED.
Conclusion;
In this tutorial, you’ve learned what a breadboard is, why we call it a breadboard, how the breadboard works internally, how we connect components to it, how we provide power to it and how to build a simple circuit on it. In case you don’t have a physical breadboard, you can use a variety of free simulating software programs such as Fritzing to build your own circuits on a virtual breadboard with schematic views for all the circuits you build.