Wires are lines that connect circuit elements in the circuit diagram.
In actual life, the wires might be pieces of copper that are connecting
the different elements, but in a circuit they're going to be basically lines.
Wires also have zero resistance and zero voltage drop.
We know that that's not true in life, everything has some internal resistance.
But for the basics of circuit analysis,
we can assume that they have zero resistance and zero voltage drop.
Wires also help to form nodes and
junctions which we'll discuss a bit more later.
Now, the circuit elements that are present in this circuit are first,
an independent voltage source.
We see it has a plus and a minus with a circle around it.
It's an independent voltage source because it's defined by the user.
It might be five volts or ten volts but the voltage source is what
it is regardless of what else is going on in the circuit.
Later on you'll learn about dependent voltage sources that actually depend on
other factors in the circuit.
This circuit also contains an independent current source.
It's an arrow that's pointing in either direction with a circle around it.
Now, please note that even though the plus and the minus are top and
bottom in the independent voltage source and the arrow points up
in the independent current source, these could easily be flipped.
For the current source the arrow could be pointing down.
For the voltage source the plus and
the minus could be rotated such as that the plus is at the bottom.
It just tells you the reference direction for current flow or for the voltage drop.