- slide 1 of 3
What are the basic constituents of an electrical circuit? Of course a power source, conducting paths, and a load. Theoretically the connections and functioning of a particular circuit may look pretty straightforward. However building an electrical circuit physically and making it work can be totally a different ball game.
Suppose, you have a schematic and are interested in testing it practically or want to construct your own designed electronic prototype, let’s say you want to illuminate a few LEDs using a power source from a power supply unit. Definitely, procuring the required parts won’t be difficult, and also a continuously variable DC power supply unit should be readily available to you.
The most difficult part lies in integrating the components together into the required circuit configuration. Nope, you can’t do it by twisting their leads together - that can be tiresome and clumsy. Using a soldering iron may be handy for the experts, but a neophyte can make a total mess with it.
Moreover for a beginner, trials using such rather complicated methods will mostly produce failures and will also eliminate the chances of reusing the components involved.
The makers of breadboards must have realized this problem a long time ago, and that’s why we now have this intelligent piece of circuit construction device at our disposal- exactly for the purpose.
One may simply use a breadboard for inter-connecting different electrical and electronic components together by plugging them into its sockets and easily build and observe a prototype circuit working without the need of using tentative and cumbersome means like a soldering iron.
Wondering how to use a breadboard? As complete a breadboarding tutorial as I can come up with is discussed here, so let’s move on.
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What’s a breadboard?
Basically breadboards are modules having numerous discrete tiny spring-loaded sockets arranged in definite rows and columns. These rows and columns are linked group wise internally through copper tracks in smart patterns which may be diversely suited to vastly different circuit design applications. By just following these built-in connections carefully, many circuit integrations and combinations may be created by simply inserting the component leads and jumper wires into the relevant randomly selected sockets.
A breadboard helps an electronic assembler to build a circuit quickly through temporary jumper wire inter-connections of the various components and also provides him with the facility of reusing the components later on for other applications.
For better understanding regarding using a breadboard practically, you may try assembling a simple LED flasher circuit over it. The diagram presented here will help you with the easy connections involved with the procedure. While building it, please note how the unused inputs of the IC 4093 are essentially terminated to the nearest logic level potentials (positive or negative). You may compare the above track layout of a typical breadboard if you are doubtful about any of the shown jumper connections. But before you proceed with the project, I would suggest that you read the following section first.
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Building Circuits Using Breadboards – Precautions
Using a breadboard may be simple, yet there are a few prerequisites and some precautions that need to be observed while handling it.
The following careful handling tips can definitely save you a lot of time and trouble while operating with this useful equipment. It’s assumed that the person who is building a circuit project is well versed with electronic basics. Throughout this section, links to other Bright Hub articles that contain more information about the particular topic are provided when possible. (All links open in a new window or tab so you can keep this page open.)
- If your circuit design is basic, choose a smaller size breadboard. Preferably, you may procure more than one such board so that you always have the option of locking them together in case you find your circuit is not accommodated by a single board.
- Instead of beginning haphazardly, make sure all the ingredients required are gathered and are well within your reach. These may specifically include mechanical tools like needle-nose or hog-nose pliers, a wire nipper, a wire stripper, a bundle of insulated single-core (not stranded) wire, and of course all the electronic components required for assembly as per the schematic.
- You may nip off the component leads appropriately so that they do not fit clumsily.
- Leadless components like potentiometers will need small rigid single core soldered terminal extensions to facilitate easy insertion to the breadboard.
- Cut and strip at both ends (5mm) a few (as per the density of connections) pieces of the above mentioned single core wire of suitable lengths (2 to 3 inches). The wire should be ideally around 23 SWG in thickness. These will act as jumper wires or conductors for inter-connecting the various component terminals.
- While breadboarding a circuit, the component distributions may not be that critical, but their positioning will definitely require serious attention.
- Always select the top extreme rail for the positive and the lower extreme for the negative or the ground connections. These rails will provide you with ample pin out sockets creating wider connecting options with the supply terminals.
- The signal input and the output of the circuit should be directed towards the left and the right hand side of the board respectively.
- Exploit the copper pattern layout of the board to the maximum such that a minimum number of jumper wires are utilized, reducing unnecessary crowding.
- Begin by fixing the ICs first; preferably straddle it across the center gap. If more than one IC is involved, make sure they are separated by columns carrying at least ten holes.
- Start connecting the remaining relevant components to the breadboard sockets which directly reach out to the IC pins. The additional components common to the IC pins may be connected through other sockets situated in more spacious areas using jumpers.
- Avoid cramming the components and jumpers into particular compact areas; use the whole breadboard space uniformly so that tweaking and troubleshooting the circuit becomes easier.
- Remember the outer body of your breadboard is made up of plastic, so avoid exposing it to extreme heat. Do not flush-fit components likely to get hot like wire-wound resistors, power transistors, lamps, etc.
- If your circuit design is critical involving highly sensitive parameters, then using a breadboard assembly probably won’t be a good idea, because the close proximity of their tracks and the jumpers may induce stray capacitance producing spurious results.
- Do not apply mains voltages directly to the breadboard circuitry because again the closely situated connections may possibly create arcing or even dangerous short circuits and a fire.
The breadboarding tutorial presented here is a brief outline of the entire subject, but it should get you started. Need more details or have specific questions? I can move ahead with deeper explanations by answering your comments, so feel free to post your thoughts. (Comments need moderation and will take time to appear.)
Breadboard and Wiring - http://courses.engr.illinois.edu/ece343/breadboard.htm
Vanderbilt University - http://eecs.vanderbilt.edu/courses/ee213/Breadboard.htm