Breadboarding Tips

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Remember these points when you wire a circuit that uses a DIP (dual inline package):

• Straightening a Bent Pin
  • Before you insert a DIP into the breadboard, look at its pins to make sure they're all straight. If a pin is bent, use a mechanical pencil to straighten it. To do this:
    1. Retract the pencil's lead so that the hole in the pencil's tip is open.
    2. Carefully slip the bent pin into the pencil's tip, as shown in the photograph below.
    3. Gently straighten the pin.
       
• Inserting a DIP
  • When you insert a DIP in the breadboard, make sure that the pins on one side of the DIP are not connected to the pins on the other side of the DIP. This means that the DIP must straddle one of the long gaps that divide the breadboard into separate sections.
  • In the photo below, the DIP on the left is inserted incorrectly. The DIP on the right is inserted correctly.
    
  • If you look closely at the breadboard, you'll notice that some of the gaps between sections are wider than others. (See photo below.) You'll have better results if you place your DIPs so they straddle the wide gaps and avoid the narrow gaps. DIPs placed over the narrow gaps have a tendency to pop back out of the breadboard because the board surface is uneven there.
    
  • When building a circuit that uses two or more DIPs, don't place the DIPs right next to each other. Rather, leave some space between them so that you can run wires between them. In the photo below, the two DIPs on the left are spaced too close together. The two DIPs on the right are properly spaced.
    
  • Orient all of your DIPs in the same direction. If you're laying out the DIPs horizontally, then make sure they're positioned so that each DIP's pin #1 is in the lower-left corner, not in the upper-right corner.
• Using Power and Ground Busses
  • For power and ground connections to your DIP, use the busses on the breadboard. On the trainers in our EET labs, these busses are located at the top, the center, and the bottom of the breadboard. The photo below shows the busses highlighted in yellow.
    
  • The close-up photo below shows more detail. Notice the red and black lines, which indicate how far the busses extend. In particular, notice that:
    • Each red line extends across twelve holes. These twelve holes are all connected together. So if you connect a wire from any one of these holes to the trainer's +5 V power supply, then the other eleven holes will all be at +5 V.
    • Each black line extends across twenty-four holes. These twenty-four holes are all connected together. So if you connect a wire from any one of these holes to the trainer's ground (GND) terminal, then the other twenty-three holes will all be at ground.
      
  • You can extend the busses by using short jumper wires to connect two or more busses together. The photo below shows red jumper wires connecting the red busses together, and black jumper wires connecting the black busses together. This way, you'll have busses that extend across the entire width of the breadboard, providing plenty of connection points for any DIPs that need to be connected to power or ground.
    
  • Once you've placed your DIPs on the breadboard, run power and ground to each DIP by following these steps:
    1. Run a red wire from the trainer's +5 V terminal to a red bus.
    2. Run a red wire from the red bus to each DIP's power pin.
    3. Run a black wire from the trainer's GND terminal to a black bus.
    4. Run a black wire from the black bus to each chip's ground pin.
  • The photo below shows two properly placed DIPs whose power and ground pins are connected to the busses.
    
• Wire Colors
  • Use red wires for connections to power (+5 V).
  • Use black wires for connections to ground.
  • Use other colors (not red or black) for all other connections.
  • In some later electronics courses, you'll build circuits that use +12 V and −12 V power supplies as well as +5 V. For these circuits, use
    • Red for +5 V
    • Black for ground
    • Yellow for +12 V
    • Green for −12 V
• Wire Lengths
  • As you wire your circuit, keep the wires short and keep them down low against the breadboard, not looping up in the air. If you can't find a pre-cut wire of the right length, then cut one to fit.
  • When you cut a wire, cut it at a 45º angle instead of 90º. This will make it easier to insert the wire into a breadboard hole.
• Straightening and Trimming Wire Ends
  • Straighten the stripped end of each wire before you insert it into the breadboard. Bent ones have a tendency to break off. If the stripped end is so badly bent that you can't straighten it, then cut it off and strip a new end.
  • As mentioned above, your wires will be easier to insert if you cut them at a 45º angle instead of 90º.
  • Trim each wire's stripped end short enough so that when you insert it into a breadboard hole, no exposed metal is visible above the breadboard.
  • The photo below shows a wire that is not properly trimmed. Notice that bare metal is exposed above the surface of the breadboard.
    
• Providing Access to the DIP
  • As you wire your circuit, be sure to leave yourself easy access to the DIP's pins so that you can touch them with a probe and so that you can replace the DIP without disconnecting any wires. In particular:
    • Never pass a wire over a DIP. Instead, route the wires around the DIP.
    • When you run wires to a DIP, use the breadboard holes farther away from the DIP before you use the holes that are closer.
  • The photos below show two poorly wired circuits. Note that the wires are much longer than they need to be and that they pass over the DIPs, making it difficult to access the DIP's pins. Imagine how difficult it would be to replace one of the DIPs
    
  
  
  
  • The photo below shows a correctly wired circuit. Note that the wires are short, low, and neatly ordered. Imagine how easily you could replace one of the DIPs without disconnecting any wires.
    
• Removing a DIP
  • To remove a DIP from the breadboard, gently pry up one end of the DIP with a pointed object (such as the tip of a multimeter probe or a logic probe), and then carefully remove the DIP without bending its pins.

Nick Reeder | Electronics Engineering Technology | Sinclair Community College

Send comments to nick.reeder@sinclair.edu