Breadboard and Wiring

Breadboards provide you with a general wiring fabric in which to make connections among circuit components. Learning how to use this wiring fabric effectively takes time and, more vital, practice. Figure 1 shows you the basic layout of the breadboards

Figure 1: Basic Breadboard

As you can see, the surface of board is covered in pinholes into which you can insert wires or electric component leads. Beneath the plastic surface, the holes are connected with a network of metal tabs. But not all pinholes are connected together. Every row in each of the two main columns is wired together. [Note: The rows are NOT connected across the column.] You can also see a series of pinhole groups arranged in columns along the left and right sides of the board. These are useful for wiring global signals and power supply voltages.

Figure 2: Special Sections for Global Signals

Making a connection between two components is simple once you understand the internal wiring of the board. Let’s take a simple example of connected two resistors in series or in parallel. The general wiring fabric of the breadboard provides an unlimited number of possibilities, but we want to focus on the efficient implementations. Never use more jumper wire than necessary! Let the breadboard do the work for you.

Figure 3: Basic Wiring Combinations

Figure 4 shows 3 examples of series wiring and 2 examples of parallel wiring. The pinholes where the component leads connect to the board are exaggerated with big circles.

Figure 4: Example Uses of the Breadboard

These few examples show you the basics and give you enough knowledge to do the labs. A few general points to remember when you begin wiring a circuit:

• Try to use the breadboard to make connections, i.e. avoid the use of extra jumper wire. Murphy’s law tells us that the more wire you use, the more likely you are to make an error by shorting two wires or incorrectly wiring the circuit.

• When you use extra jumper wire, keep it as short as possible. The lab kits provide jumper wire of various lengths. Use them all! A mess of long wires creates the “St. Louis Arch” syndrome, where all your wires make glorious arches over each other. Now you can’t be expected to appreciate why these arches are electrically undesirable (They act as antennas), but you can appreciate how easily they complicate your life. If your circuit looks like a bush of wires, imagine how hard it will be to debug it when [Note: not if] it doesn’t work correctly.

• Keep related components together.

• Make the circuit on the breadboard look as much as possible like the schematic you’re implementing. The visual correspondence will help you differentiate the various nodes; plus, your TA can do more to help you debug if he can easily make sense of your circuit.

source:http://courses.engr.illinois.edu/ece343/breadboard.htm