How to Use a Breadboard and Build a LED Circuit
A breadboard is a great tool for quickly testing out a prototype circuit or hooking up a quick experiment. Breadboarding is an important step in testing out ideas or learning how things work. When I first started tinkering with electronics I discovered that everyone assumed that I would know how to use a breadboard. I wasted quite a bit of time wondering what I did wrong or if my Arduino was broken before I figured things out.
This tutorial is for those who are just getting started and want to brush up on the basics before diving in. In this tutorial I will explain the basics of how a breadboard is laid out and and offer some tips on how to keep things manageable as your creation or experiment grows on your workbench.
Things you will need for this tutorial:
- Momentary on switch
- 220 Ohm Resistor
- 4 AA or AAA battery pack
- Jumper wires (22 gauge)
Things you might want generally for your kit
The typical breadboard is laid out in a matrix of .1 inch spaced holes. Most through hole Integrated Circuit chips or ICs will fit snuggly in this matrix. Also, many headers and “breadboard friendly” components will fit nicely. Which holes you plug them into does matter. So lets take a look at how the breadboard is laid out.
For this exercise we’ll orient the breadboard vertically so that the short side is at the top and bottom. The pictures below will make the orientation clear. Apparently there is a bit of religious debate between vertical and horizontal board users as to the proper orientation of the board, however the consistent advice from either party is do what makes sense for you.
You can see from diagram that the pins of the IC are now accessible by inserting a component or jumper wire in the available horizontal pins and connecting to another row.
These power rails are also isolated to the right and left side of the breadboard. If you have to manage two different power supplies or voltages, they can be isolated by keeping them on either side of the board.
For ease of use many people link left and right side of the board so voltage and ground are handy on both sides of the center.
Some boards like the board I linked to in the components list have binding posts for attaching power. You can see an example here
In all cases that I have reviewed, these are not connected to the breadboard rails in any way and it is up to you if you wish to use them or connect them to the power rails. If you have a breadboard with binding posts, make sure to verify this before you use them.
In general, though, the posts are an easy way to connect from a bench top switching power supply to your breadboard. When I draw power from the pins from an Arduino or Raspberry Pi, for example, I generally jumper these directly to the vertical power rails and detach the power supply from the posts.
General Breadboard Tips
The cool thing about breadboards is that they can be used thousands of different ways and there are no hard rules. This makes throwing together project quick and easy. I’m offering you a few tips here that can help make your projects more sustainable and readable. Following a few simple guidelines can help you avoid simple mistakes in wiring.
Do What Works for You
If the circuit works and you are happy you are successful. The other tips below are just that, tips. They are suggested to help bring visibility, repeatability, and easy debugging to your projects.
Choose a Color Scheme and Stay Consistent
- Black for Ground*
- Red for +V*
Use other colors consistently in your work to help with debugging and reading your circuit. i.e. green for tx and yellow for rx.
*May vary by convention in different countries
Hard Jumpers for Routing on Board
Use 22 gauge jumper wires, prefabricated or handmade, to route wires on the breadboard itself. Press them firmly into the board and lay them out like traces on the breadboard. This will help you see the circuit more easily in contrast on the breadboard.
Choose Best Fit Prefab Jumpers or Custom Cut Lengths
To keep the board clean and your circuit easily visible, try to use the best fitting jumper wire, or custom cut and strip one from that kit of hookup wire I mentioned above.
Bend Wires Around Components for Visibility
As you lay the jumper wire traces on the board, route them carefully around other components to leave them visible and allow you to easily retrace them when you return to your project after a break or are attempting to debug issues.
Avoid Crossing Wires Unless Necessary
When building up a complex circuit on a breadboard it will eventually be necessary to jump over wires with new wires. However, the more you can avoid this, the easier it will be to read your circuit for debugging, documenting or after you've slept.
Use Flexible Jumpers for Linking Off Board
Use flexible jumper wires to jump from the breadboard to other components such as an Arduino or Raspberry Pi. The flexible wires will allow you greater flexibility when moving your boards around or re-configuring. Keep with the color scheme you started even with these wires.
Other Prototyping Tools
Even though setting up a breadboard is very simple, you don’t even need a breadboard to start playing around. Here are a couple suggestions to let you plan out a project before you even break out your breadboard.
Fritzing is an open-source software project that gives you the ability to lay out your project on a breadboard as well as add components from a large library of chips, boards like Arduino, and discrete components. Fritzing is at fritzing.org
123D Circuits is a web based software prototyping application. It allows virtual layout as well as tutorials and help pages. It includes the concept of sharing and collaborating on circuit design as well as creating Gerber files for the creation of custom PCBs.circuit board 123D Circuits (http://123d.circuits.io)
Basic Pushbutton LED Tutorial
Lets put some of these practices and tools to work in a simple example.
Attach the battery pack to the power and ground rails of the breadboard.
Plug the switch into the breadboard. This picture shows it hurdling the center line but the top and bottom pins are connected when the button is pushed rather than the left and right. This position simply leaves us lots of room to route the other wires.
Insert the LED with the anode (long leg) towards the top of the board.
Insert the resistor into the board with one end in the same horizontal row as the LED’s cathode (short) leg and the other a few rows down. The resistor is not polarized so it does not matter which direction you insert it.
Wire up the positive leads using red jumper wires. Then connect from the positive rail of the breadboard to the same horizontal row as the top leg of the switch. Now connect from the row that houses the bottom leg of the switch to the row that houses the anode of the LED.
Wire up the ground lead from row that houses the bottom of the resistor to the ground rail of the breadboard. Check your work against the diagram below.
Press the button and the LED should light up. Congratulations, you've assembled your first breadboard circuit.
Using a breadboard is very simple. It’s a great tool for fast and easy prototyping. In this tutorial you learned how a breadboard is setup, general tips for easy to use and read breadboard layout, tools for virtual prototyping and how to build a simple circuit on a breadboard that lights an LED when you push a button.
The general rule for breadboarding should be “if it works for you, do it.” In addition, following a few extra guidelines can help your project be easier to build, troubleshoot, and eventually transition into a permanent housing.