Switching Basics and More 65Experiment 8: A Relay OscillatorBreadboarding the Circuit
I promised to free you in time from the frustrations of alligator clips, and that
time has come. Please turn your attention to the block of plastic with lots of
little holes in it that I asked you to buy. For reasons that I do not know, this is
called a breadboard. When you plug components into the holes, hidden metal
strips inside the breadboard connect the components for you, allowing you
to set up a circuit, test it, and modify it very easily. Afterward you can pull the
components off the breadboard and put them away for future experiments.
Without a doubt, breadboarding is the most convenient way to test some-
thing before you decide whether you want to keep it.
Almost all breadboards are designed to be compatible with integrated circuit
chips (which we will be using in Chapter 4 of this book). The chip straddles
an empty channel in the center of the breadboard with rows of little holes ei-
ther side—usually five holes per row. You insert other components into these
holes.
In addition, the breadboard should have columns of holes running down each
side. These are used to distribute positive and negative power.
Take a look at Figures 2-72 and 2-73, which show the upper part of a typical
breadboard seen from above, and the same breadboard seen as if with X-ray
vision, showing the metal strips that are embedded behind the holes.
Figure 2-72. A typical breadboard. You can plug components
into the holes to test a circuit very quickly.
Figure 2-73. This X-ray-vision view of the breadboard reveals
the copper strips that are embedded in it. The strips conduct
electricity from one component to another.