So now we've assigned our meshes and

we've assigned our mesh currents that's the first step in mesh analysis.

Then the second step is to go to each one of these meshes and to add up or

sum up the voltages around the loop that close path, which we have.

Starting at the, typically I start at the lower left hand corner and

going around the loop, back to that same corner.

So we'll do that for each one of our loops.

We'll go all the way around it from start to finish,

ending in the same point, summing up the voltages.

What we're going to find in this problem is that we have a couple of

issues with using this straightforward approach and doing the problem.

So we have to use some of our additional rules of mesh analysis and

Kirchhoff's voltage law.

So let's start with Loop 1 which is the upper left hand corner.

We need to sum up the voltages around this loop.

So if we start in the lower left hand corner,

we start up, we see that we run into a 3 milliamp source.

We don't know what the voltage drop is across this, so we'd have to assign

another variable D sub 3 milliamps for the voltage drop across it.

So we'd add another variable in addition to our Mesh current.

Our four mesh currents would have a fifth variable in that case.

And we could go on around and we can find the voltage drop

across the two kilo ohm with respect to the loop current I1 and I sub 2.

And the 4k we could do the same using I1 and

I4 and the current as, to find the current through the 4k.

But we have this problem with the 3 milliamp resistor or

3 milliamp source on the left hand side of the circuit.