USING THE BREADBOARD

In the previous sections, we talked about circuits, how they work, how we build them and how we represent them on a schematic diagram. We even built our first circuit using a battery, a resistor, and LED and some wires.

When it comes to building circuits in real life, connecting wires and components together like we did above – either twisting the wires together or soldering them together – is certainly one way to do it. While sometimes it makes sense to build circuits by twisting wires together or soldering, the problem is that these modifying these types of circuits can be very difficult and cumbersome.

In many cases, you’ll want to build temporary circuits that are easy to modify – this lets you “play around” with the circuit and work out the kinks in your design; then, once you have a temporary circuit that is working exactly the way you want, you can use the design as the basis for your permanent circuit.

One of the most common ways of building a temporary circuit involves the use of a “breadboard,” which you may also hear referred to as a “proto-board.” The name breadboard stems from the fact that early electronics hobbyists would often use the large wooden boards designed for rolling out and cutting bread dough to house their temporary circuits.

The breadboards used to build electronics are often called “solderless” breadboards, which can help avoid confusion when talking to your pastry chef friends.

Breadboard Design

Breadboards come in many shapes and sizes, but the fundamental components of the breadboard will remain the same:

We’ll get to the purpose of each of these parts in a moment, but the key to a breadboard’s usefulness is how the various areas are electrically connected. Those connections are illustrated here:

As you can see, each of the two rails consists of two long row of connections (a red row in each rail and a blue row in each rail). There are spaces between the groups of holes in the rail, but the entire row is still electrically connected as indicated. Also note that the two red rows are not connected and the two blue rows are not connected – they are denoted in the same color only because they serve the same purpose.

In the center of the board, each row of five connect strips are electrically connected together. While I only highlighted a few rows of connect strips, in actuality, every row of five is a connected strip. It’s important to note that there is no electrical connection across the notch – there’s good reason for this which we’ll get to in a bit.

If you recall from Introduction to Electronics, in order to have a closed circuit, electricity must be able to flow from power, through the circuit, to ground. A breadboard makes it easy to wire a circuit in this fashion – the rails contain the start of the circuit (power) and the end of the circuit (ground), while the connect strips provide space for your components and the connections between those components.

Powering the Breadboard

Of course, the circuits you build on your breadboard are going to require power to operate.  When it comes to providing power to the breadboard (and to the circuits on them), there are lots of options.  

In our first breadboarding project, we will be using our little 3V lithium battery to power our circuit.  After that, we will start using power that is supply directly through the RaspberrySTEM kit.  In addition, if you ever use a breadboard outside of the RaspberrySTEM kit, you'll find that there are power supplies built specifically for breadboards. And you always have the option of finding your own power source (battery, solar cell, AC power adapter, etc) and hooking that up to your breadboard as well.

We'll go into step-by-step detail on how to hook up power to your circuits using in our upcoming projects, but just be aware that there are lots of options for power sources for your circuits when using a breadboard.