132 THE OFFICIAL RASPBERRY PI BEGINNER'S GUIDE
Using a breadboard
The next projects in this chapter will be much easier to complete if you’re using a breadboard
to hold the components and make the electrical connections.A breadboard is covered with holes – spaced, to match components, 2.54 mm apart. Under
these holes are metal strips which act like the jumper wires you’ve been using until now. These
run in rows across the board, with most boards having a gap down the middle to split them in
two halves. Many breadboards also have letters across the top and numbers down the sides.
These allow you to find a particular hole: A1 is the top-left corner, B1 is the hole to the immediate
right, while B2 is one hole down from there. A1 is connected to B1 by the hidden metal strips, but
no 1 hole is ever connected to any 2 hole unless you add a jumper wire yourself.
Larger breadboards also have strips of holes down the sides, typically marked with red and black
or red and blue stripes. These are the power rails, and are designed to make wiring easier: you
can connect a single wire from the Raspberry Pi’s ground pin to one of the power rails – typically
marked with a blue or black stripe and a minus symbol – to provide a common ground for lots of
components on the breadboard, and you can do the same if your circuit needs 3.3 V or 5 V power.
Adding electronic components to a breadboard is simple: just line their leads (the sticky-
out metal parts) up with the holes and gently push until the component is in place. For
connections you need to make beyond those the breadboard makes for you, you can use male-
to-male (M2M) jumper wires; for connections from the breadboard to the Raspberry Pi, use
male-to-female (M2F) jumper wires.
Never try to cram more than one component lead or jumper wire into a single hole on the
breadboard. Remember that holes are connected in rows, aside from the split in the middle, so
a component lead in A1 is electrically connected to anything you add to B1, C1, D1, and E1.The five holes in each
column are connectedAll the holes in each
rail are connected