Used in prototyping and maker electronics, solderless breadboards might seem strange if you don’t know how they work!
You may have been expecting to see Radio Part 3 in this month’s FUNdamentals. Well, this was originally the intention, but we quickly realised that FUNdamentals and The Classroom were both dealing with fairly complex topics. While The Classroom is indeed intended to do so, FUNdamentals was intended to do precisely as you’d think - cover the fundamentals. For this reason, we’ve determined that Part 3 of our detailed explanation of Radio will now appear under The Classroom in Issue 16. This will get FUNdamentals back to where we expect it to be, bridging the gap between absolute novices and maker proficiency. We apologise for any inconvenience if you were indeed looking for Radio Part 3, but being the overachievers that we are, we wanted to make the adjustment as soon as possible!
In the early days, simple electronics circuits were made by wiring components onto nails hammered into a wooden board. Those boards were literally the board used to slice the bread on. Hence the name "breadboard".
Nowadays, "solderless breadboards", like the one shown above, are the go-to platform for many makers to prototype their circuit. Commonly they are referred to as just "breadboard", and as we will explain, allow you to use components over and over, unlike "solderable breadboards", commonly referred to as prototyping board or veroboard.
WHAT IS A BREADBOARD GREAT FOR?
When it comes to testing basic circuits, development of new ideas, testing components, there’s really no better solution than a breadboard.
If you’re developing a circuit, or temporarily constructing something, then a breadboard is perfect due to its low impact on the components being used. You can basically use them time and time again on a breadboard, with no impact on the components themselves - provided you take care of them.
You will notice that there are many projects we feature in DIYODE that use breadboards. For instance, in this month's Lighting Controller project we demonstrate the switching circuit on a breadboard.
Certainly, most of our Kid's Basics projects use breadboards, because it's a lot easier for kids to follow the wiring instructions going by the photos and illustrations. It also avoids the need for soldering, which is another skill to learn.
WHAT IS A BREADBOARD NOT GREAT FOR?
Complex circuits quickly become a tangled mess when they start getting too many components and connections. Though even for complex circuit development, breadboards can still be very useful as long as you understand their limitations.
No, they don’t make actual noise you can hear - we’re talking about electrical noise. The thing that makes them very easy to use, is also part of what makes them electrically noisy. If you use an oscilloscope, you can often see the electrical signal you’re expecting, but often there are residual and unexpected signals too - we call that electrical noise. In many maker circuits it’s not a problem and can be virtually ignored, but it’s there. If you’re dealing with sensitive equipment, breadboarding may not be a suitable option. However, for most digital electronics and basic circuits, it’s perfectly fine!
As your breadboard ages and sees a lot of use, things inevitably start to wear out. Once these connections start to wear a little, they can become a little less reliable. You may find that you’re chasing a problem that is not actually in the circuit design but due to a breadboard connection. They can also have an impact on more sensitive systems such as high-speed serial, and wireless devices. They often work fine - but it’s important to consider their limitations.
However even with these factors considered, breadboards are a powerful prototyping tool, and something you should become very familiar with.
As with just about every product ever made, there are huge differences in quality. While ultra-cheap breadboards may seem like a good idea, you can find yourself running into some problems.
Some of the common issues we've seen are usually manufacturing faults, rather than by-design cost reductions. They often manifest as holes that don't align correctly with the internal connections.
You may find yourself unable to push a pin into the hole, or if you can, it may not make any sort of electrical connection. Either way it's no good, and you may not even realise!
The quality of the metals used may also be inferior, and you may simply find it works fine for a while, but quickly degrades. A quality breadboard will usually provide years of faithful service.
One thing the electronics industry does relatively well is standardising things unless there’s a proprietary reason not to do so. That makes things really handy because you don’t have to worry about the spacing between pins for many items.
For a long time, the standard pin spacing has been 2.54mm. We know - that doesn’t sound very practical in a metric world, but it does of course also mean 0.1-inches on imperial measurements. Pins may be further apart on some devices, but they’ll usually still be a multiple (5.08mm / 0.2-inch) etc.
This pin spacing is also commonly referred to as “pitch”. The standard 2.54mm/0.1-inch pitch is most commonly used in terminal strips and connectors intended for circuit-board connection, as well as through-hole integrated circuits (ICs).
It means that connecting multi-pin items, such as integrated circuits, and terminal blocks, can all fit into a breadboard. Can you imagine how much more difficult it would be to prototype if they didn’t? Chaos!
Fortunately for makers, many of our favourite microcontrollers such as Arduino and Raspberry Pi also adopted these 0.1 inch terminal standards. This was probably, in part at least, due to simple availability of those standardised parts, but it really makes connectivity simpler.
It means that you don’t need a set of Raspberry Pi compatible jumpers, Arduino compatible jumpers, and whatever else you have. Sure there are male and female type jumpers, but they’re otherwise totally interchangeable with each other.
WHAT MAKES IT SOLDERLESS?
Soldering a component is the best way to form an electrical connection to a circuit, but what if you’re just testing or doing something temporary? Desoldering is possible, but the heat can damage components, and it’s a lot of effort if it’s not required.
Inside the breadboard is a u-shaped piece of metal, which takes a firm hold of any component, jumper wire, or anything else you push into it. This u-shaped piece of metal is the genius behind solderless breadboarding. It provides enough friction that your standard components won’t fall out (though we don’t recommend turning them upside down when full of components), but won’t damage the component at all, even when inserted and removed a number of times. The hole in the plastic case of the breadboard helps guide the wire to the u-shaped clamp, so using them is extremely easy. The plastic also acts as a separator and insulator between component legs.
In a breadboard context, each hole is often referred to as a “tie point”. You may see breadboards noted as “400 tie point” or similar - it’s really just an indication of overall size, and doesn’t tell you much about the configuration, but still, useful information to have.
This is really great, but how do components then get an electrical connection to each other? That’s what terminal and bus strips are for, which are inside the breadboard.
TERMINAL AND BUS STRIPS
All of those hundreds of tie points aren’t really much use to us unless they have a way to connect components electrically. Fortunately for us, that’s precisely what terminal and bus strips do!
Electrically, terminal and bus strips are pretty much the same - but in breadboarding they provide two very different functions for us.
These are the electrical backbone of breadboards. They are what connect our components together electronically, inside the breadboard.
Each of the u-shaped connectors on each tie point, are actually part of a larger part of metal, which connects a number of tie points together in a row.
Each terminal strip runs parallel to the next. Therefore tie points are electrically connected to their neighbours left and right, but not up and down (or vice versa, depending on how you look at the breadboard).
For example, in the breadboard shown above, pins A to E are electrically connected and pins F to J are electrically connected, with a gap in between. Each row is the same.
One handy addition you’ll often find on larger breadboards is a bus strip. Not all breadboards will include a bus strip, but they’re often very useful.
A bus strip is designed to easily distribute power to your breadboard full of components. There are usually bus strips that run along the entire side of the breadboard to make wiring easier. You should notice that these strips are colour coded for positive and negative power rails. We’ll cover powering the breadboard later in this article.
Note: If your breadboard doesn’t clearly identify the positive and negative strips you can run a coloured permanent marker along the entire bus strip (Red for positive and Black for negative).
THE GAP DOWN THE MIDDLE
You’ll likely have noticed that there’s a channel running down the middle of your breadboard. This gap is a break in the electrical conductivity between both sides. What you have on one row is not connected to the same row on the other side of this gap at all.
Conveniently the gap is also sized to a standard, providing you with electrical separation for DIP (dual inline package) devices such as discrete ICs, DIP switches, and other components you wouldn’t otherwise be able to use on a breadboard. Very handy!
Almost all breadboards include jig-saw style notches along each edge which allow you to basically connect breadboards together. While they don’t create any sort of electrical connection, they provide a fairly good way to expand the capacity of your breadboard for large prototypes and projects.
You could simply put them side-by-side, but locking them together helps avoid wires pulling out if you move or bump the breadboards.
Though it’s probably worth noting that you still can’t really pick up and move them after more than about three are linked. That is, without potentially undoing hours of work!
Jumper wires are a mainstay of the maker toolkit and are what we use to connect different pieces of hardware together. However, there are two types of common connecting wires. Those are solid link wires, and jumper wires. They are referred to by a few other names too, however, the following images and explanations will assist.
These are insulated pieces of wire which are often fairly rigid. It can be a solid piece of copper or stranded wire with tinned ends. The wire is exposed at either end and bent at 90° so you can insert the ends into your breadboard. These are really useful for connecting different strips on your breadboard, without creating a wiring mess. They come in various sizes and span just two holes, up to 10-15cm depending on the supplier.
They are not typically used for non-breadboard connections, though being human, we’ll occasionally find strange ways of using various hardware.
Jumper wires are also a staple in the maker toolbox, creating most of the connections between your microcontroller, modules, breadboards, and anything else you may have attached. They’re generally available in male-to-male, female-to-female, and male-to-female configurations. Multi-packs are a great source of jumpers, to cover virtually all configurations you might require.
They’re made from stranded wire, so they’re nice and flexible and come in various lengths; commonly about 15cm but available in longer lengths too. At each end you’ll find a pin connector, often referred to as a Dupont connector. The female version of these will connect on to standard pins (found on modules, Raspberry Pi boards, and more), while the male ends will connect to headers (found on many Arduino boards) or pin sockets such as your breadboard!
Then it’s just up to you to select a jumper wire with the ends appropriate for the connections you’re making.
It’s worth noting that both solid link wires and jumper wires are often supplied in various colours. The colours themselves are generally meaningless - unless you use your own convention. Here at DIYODE, we tend to use whatever is at hand. However, we’ll often reserve red and black wires for positive and negative connections respectively, simply to avoid confusion if used in reverse. A black (negative) wire on a positive (red) terminal can quickly lead to confusion.
POWERING THE BREADBOARD
There are multiple ways to provide power to your breadboard. In many projects from DIYODE, power will be provided from an Arduino or Raspberry Pi board, which is connected to either a USB port or power pack.
Dedicated breadboard power supplies are available from electronics stores that plug directly into the board. These usually draw power from a USB port, power pack or even a 9V battery. These clever devices usually have a switch to select either 3.3V or 5V power outputs depending on what your circuit requires.
Whatever power supply you choose, make sure it is a regulated type to avoid higher voltages going to your circuit and damaging the components.
It may start to get confusing when trying to reference locations on a breadboard. After all, you might have a breadboard with 800, or even more connections available!
Fortunately, someone thought about this ahead of time and came up with a genius solution, borrowed from maps.
While not all of us will remember, the traditional printed street maps used x and y coordinates to give an approximate location.
While these are still used today, not all of us look at a map not attached to a Google Assistant or other GPS function.
Breadboards use a letter / number system, not too dissimilar to this. The letters denote a column, while numbers denote a row.
From left to right, the rows are grouped a to e, and f to j. Then each row is numbered sequentially from 1. This means that if you see a breadboard reference “C12”, you need to locate column “C”, and row “12”.
Likewise, if you need to give someone instructions you can use these coordinates for a clear guide to locations. As you can see it’s fairly easy to follow!
While the schematic (pronounced “skee-mattic” is the standard for electronic circuit design, there’s another method of describing electrical circuits which have risen to popularity in recent years. That is the Fritzing diagram.
While schematic design and reading can take considerable time to learn and use proficiently, Fritzing is multi-platform open source software which allows users to quickly and easily model a prototype with little to no experience required.
Indeed, while schematics have been around for as long as modern electronics, Fritzing was only first released in 2007. One of the reasons for its popularity stems from the visual depiction of the circuit itself, rather than having to learn symbols and methods. It effectively bridges the gap, meaning you don’t have to specifically know how each component works, you can simply follow the pictures, with a high degree of success.
While this is certainly useful for anyone using electronics, it’s perhaps particularly useful for coders who have a high level of knowledge of complex code development in various languages, but have not previously used electronics much. We hear from many readers that this is not an uncommon path for them to have taken.
Some engineers and makers who are familiar with traditional electrical schematics may find Fritzing diagrams useful for greater clarity and understanding of the circuit itself. We continue to provide both schematic and fritzing diagrams where they’re appropriate. For some projects such as Kid’s Basics, we won’t provide a schematic, and for some complex projects, such as our Lighting Controller in this issue, it’s not practical or sensible to develop the project on a breadboard (at least in its entirety).
WHERE TO FROM HERE?
Experiment! Grab a breadboard, some components and jumper wires. If you’ve never built anything using a breadboard before, use your newfound knowledge to tackle some of the breadboard-based projects we have described!
For simple circuits, but with real-world functionality, refer to our previous Kid's Basics articles. There's the Sensors and Servos Kid's Basics in Issue 13 and Traffic Lights for car playsets in Issue 14.
If you're hungry to learn more about electronics fundamentals, you can refer to past articles. Learn about components, such as resistors in Issue 3, Capacitors in Issue 4, Diodes in Issue 5, Transistors in Issue 6.
Of course, be sure to read the FUNdamentals article every month to expand your knowledge.