If you love to prototype circuits and create electronic designs, then you’ll be familiar with the humble solderless breadboard. It’s where most electronic projects begin and is a familiar sight for tinkerers and inventors.
Hi, my name is Sam and you’re watching another Core Electronics video. Today we’re going to be taking a look at how Solderless Breadboards work.
Now, what is a breadboard? Well, first of all a breadboard is this plastic piece of prototyping equipment that I have here. Now why is it called a breadboard? Well, originally when people wanted to prototype circuits they would take a physical wooden board, often used for slicing bread, hammer some nails into it and solder components to those points to make a circuit. But now of course we have what is known as the solders breadboard and it’s fantastic. Almost every electronic project starts out at the breadboarding stage. Now how does it work? A lot of people see this as a grid of holes and endless places you can put things in and get a bit confused and that’s understandable. It can be a little bit of a mind shift when transferring your circuit from a schematic or a design to a breadboard. It takes a little bit of getting used to how to lay it out - but don’t worry, we’re going to take a look at that today.
Now, a breadboard is a plastic board with 0.1” or 2.54 mm spaced holes and that’s a standard unit of measurement for electronic components. IC chips, capacitors and things like that will often be designed to fit in to 0.1” or 2.54 mm placed holes. We can see I’ve got an LED and a resistor here and the legs just go in - you insert them into the holes like this. Underneath are metal strips with little spring loaded V shaped contacts and when you push a component leg in there it forces itself in between the contacts and the spring holds it together and it makes an electrical connection.
On the breadboard (I’ll take this resistor off) you can see there is rows, you can see A, B, C, D, E, F so on and so forth, anyway, theres 10 across with this divider in the middle. Now on the breadboard, you’ve got these holes here, theres 5 across this way and in these rows. They are electrically connected in this orientation like that. It’s also numbered 1 down to 30 so this is a small breadboard, its a half sized breadboard. You can get bigger ones, you can get 3 breadboards lined up together, you can get even smaller ones than these and this features power rails as well which we’ll get to in a minute.
So, to connect something up you would put something in this hole, so this LED for example - let’s insert him in there. Now this component leg is connected to that row of holes and if I want to connect something to it I could take a jumper wire which is designed to work specifically with breadboards and put it in any of these 4 remaining holes and it’s going to make a connection because they are connected this way. Now this divider is an isolator against these rows so these 5 are not connected to those 5 and there is nothing connected along this orientation - this axis.
Let’s make a simple circuit, I’ve got an Arduino board here I’m just using to get some 5 V to the board and I’m going to connect it up to these power rails here. Now these operate slightly differently - they’re connected along this orientation here. So all of your negative pins on the ground rail are connected to each other and then they’re isolated from the positive rail here. Now this is useful for putting voltages on your board, you use it to supply your project with electricity. I’ve got a positive rail and a negative rail so let’s take this and i’m going to plug my ground wire into the board - alrighty, now be careful not to short these out! They will short out your board. I’m going to connect the black wire to the negative terminal and the positive wire to the positive terminal and now I have power all along those rails on my breadboard. Important to note that they are not connected to this side as well so you can 3.3 V rail on one side and a 5 V on the other side, or 12 V or how ever you want to work it. Or you can bridge them across to have the same continuous power supply across both rails. Now lets connect up a really simple circuit, LED and resistor. I’m going to connect the positive leg of my LED up to the power rail and the negative leg over to another pin. Now I’m going to take a resistor, this is a 220 ohm resistor and its a good value for limiting the current and hence brightness to our LED to make sure it doesn’t burn out. I’m putting the resistor in there with one leg connected to the same row as the leg of the LED and the other one over there and I’m going to take one of these jumper leads and insert it here. Now I want to connect it to ground and it lights up! Fantastic and that is an extremely simple circuit put on a breadboard.
Now, these breadboards sound all well and good but what are some of the drawbacks to them? Well, there’s a couple - namely that they are temporary connections, they are not soldered connections. They are solderless which means that anyone can put components in a create a circuit. If you’ve got quite a big project and you’re working on multiple breadboards and have jumper wires going everywhere you can find you have intermittent connections because if the competent leg is really thin it might not have enough force to make a really reliable connection with the spring loaded contact that is underneath. It might be a bit intermittent and things like that which is not what you want. It can be easily bumped or dropped and your circuit is going to fall apart and that’s not good either. So soldering is definitely something that a prototyping board, a strip board,a variboard is going to be a much more reliable method for prototyping. But for testing out circuits a breadboard is perfect. You will find however that breadboards have the issue of capacitance. Now a capacitor if you do remember, if you’ve read our electronics crash course - analogue electronics crash course tutorial, a capacitor is two conductors separated by an insulator and that is exactly what the pins on a breadboard are. Now its a very small capacitance - so small you will barely notice it on most projects but for high frequency, really specific RF circuits they don’t recommend that you do test it with a breadboard because each pin can have up to 5 pico farads - now thats not a lot. Pico is very very small unit of measurement but in high frequency high speed designs that is enough to throw of the timing of the signals. Just something to be aware of. Now the breadboard is great, don’t get me wrong, its fantastic. If I were to have a design I would breadboard it first and then once i know that the circuit works I would transfer it to a soldered prototyping method like some strip board or prototyping boards - something like that. So it’s just something to be aware of and the last thing is that the current rating on them is not high. You can only put about 5 W of energy across one of the breadboard terminal strips. Now what does this mean? If you’re working on a 5 V project you can draw up to 1 amp on the metal connectors underneath the breadboard before they start to get too hot and may melt the plastic. If you short something and you’re drawing lots of current you could potentially melt your breadboards so they’re not recommended for high power design either.
Hopefully this has given you a good insight into how breadboards work. You can connect resistors, LEDs, capacitors, integrated circuits that are designed to be straddled across there because it’s a standard spacing. You can connect all of these components up to the breadboard to create your circuit on your project - its fantastic. I would encourage you guys to check out some of the sizes available. I recommend the full sized breadboard and a half sized breadboard for different projects to have on hand. You can connect them up, they have these little tabs on the side that you can snap them alongside each other - they’re fantastic so get your hands on a couple. They are super cheap and that’s all for today guys thanks for watching