The anatomy of a breadboard ............................................................
The breadboard itself is a plastic board with strips of metal running under-
neath and holes in the top. You slot the little wire legs that sprout from com-
ponents and also the connecting wires into these holes, which contain metal
channels called contacts.The metal strips that run underneath connect the
items you plug into the holes to each other and the battery.Breadboards come in various sizes; however, no matter what the size, the top
and bottom rows of contacts on the breadboard (see Figure 4-7) are linked
horizontally, and you’ll typically use them to connect to your battery.How to figure out what size breadboard to get? Some have as many as 3,200
contact points! But don’t overdo. For the projects in this book, we used
boards with 400 contact points for small circuits and 830 contact points for
medium circuits; for our large circuits, we hooked two boards together with
the handy ridges and notches on the sides of the boards.Notice the + and – (negative) signs on the breadboard. The positive battery
terminal is connected to the rows with the + sign; these rows are often referred
to as the +V bus.The negative battery terminal is connected to the rows with
the – sign; these rows are often referred to as the ground bus.Because the +V
bus and the ground bus run the entire length of the board on both sides, you
need to use only a short piece of wire to reach a +V or ground bus from any-
where on the breadboard.Figure 4-7:
Your basic
solderless
breadboard
in our two
favorite
sizes.66 Part I: Project Prep