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 needle-nose pliers or a mechanical pencil to straighten
it. To use a mechanical pencil:
- Retract the pencil's lead so that the hole in the pencil's
tip is open.
- Carefully slip the bent pin into the pencil's tip, as
shown in the photograph below.
- Gently straighten the pin.
- Inserting a DIP
- On a new DIP that has never been used, the pins are usually
spread too far outward to be inserted into the breadboard. Gently
press the pins on both sides of the chip inward so that their
spacing matches the spacing of the holes on the breadboard.
- 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
- In the photo below, the left-hand DIP is inserted
incorrectly, because the pins on the lower side of the chip
are connected to the pins on the upper side. The right-hand
DIP is inserted correctly, because the DIP straddles
the breadboard gap.
- 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
- For large circuits, extend the busses by using short
jumper wires to connect 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 power or ground.
- To establish power and ground connections, run a red wire from
the trainer's +5 V power supply to the leftmost hole in
a "red" bus; and run a black wire from the trainer's
ground (GND) socket to the leftmost hole in a "black" bus.
Then run red and black wires vertically from those busses to
any points in your circuit that need power or ground. The photo
below shows two properly placed DIPs, with power connections
to pin 14 on each DIP and ground connections to pin 7 on each
- 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
This will make it easier to insert the wire into a breadboard
- 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:
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. As
an example of this, note that in the picture below, the power
and ground wires are placed as far away as possible from
the DIP, rather than in holes right next to the DIP .
- The photo below shows a poorly wired circuit. Note that the
wires pass over
the DIPs and are crowded in too close to the DIPs. Imagine how difficult
it would be to replace one of the DIPs, or even to use a logic probe
on the circuit without accidentally knocking wires out of their holes.
- The photo below shows a correctly wired circuit. Note that the
wires are short, low, and neatly ordered. You
could easily touch a logic probe to any one of the pins, and you
could replace a faulty DIP without having to disconnect any wires.
- Removing a DIP
- Do not use your fingers to remove a DIP from the breadboard. It's
too easy for your fingers to slip, causing the DIP to twist. This
results in bent pins.
- Instead, use a chip puller to gently pull the chip up from the board.