When you are building
a circuit, you
are inevitably starting
from a circuit diagram
that either you produced
or somebody else did.
So I'm going to
start like that, too.
Here is a +5 volt rail, meaning
a piece of conductor drawn
into our circuit diagram.
That's all at positive 5 volts.
And I'll draw a
ground rail as well.
And my circuit here is going
to be a very simple one.
Simply a resistor.
Maybe it's a 1,000 ohm
resistor, and an LED--
a light-emitting
diode-- to ground.
And we're going to hope that,
when we build that circuit,
it will actually
light up the LED.
So building this-- so we
start with a circuit diagram.
Building this means that
we're going to implement
that circuit on a breadboard.
And to do that, you need to know
the connectivity pattern of all
these holes on the breadboard.
So let me sketch
out how this works.
The breadboard
consists of-- I think
it has 830 holes, connection
points that you can
stick the end of wires into.
And they're arranged like this.
Two rows of them are on the
left and two rows on the right
are what are called "rails."
And they are connected,
although all the holes just
look like individual holes.
The connectivity pattern
is that these are all
connected to each other by a
conductor inside the board.
And on the other side,
there's another two.
So now, I've implemented
this circuit,
which is so clear and easy
to understand, as a circuit
diagram over here on
a piece of breadboard
where it will actually work.
But if you're trying to tell
somebody what you've done,
it sure is a lot neater and
cleaner to draw it like this
than it is like this.
