- #1
thorx440
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Homework Statement
Use the mesh-current method to find the branch currents ia, ib, and ic in the circuit in figure.(Figure 1) And find currents i_a, i_b, and i_c if the polarity of the 77V source is reversed. The values of v1 and v2 are
Homework Equations
Mesh Analysis
Mesh 1: R's in mesh 1 x i1 - R's in common between Mesh 1 and 2 x i2 = Voltage source in Mesh 1
Mesh 2: -R's in common between Mesh 1 and 2 x i1 + R's in Mesh 2 x i2 = Voltage source in Mesh 2
The Attempt at a Solution
I know this problem can be solved by simply using kirchhoffs current and voltage laws, but the problem specifically asked to use mesh current. I designated the left mesh as mesh 1 and the right as mesh 2. Mesh 1 goes clockwise while mesh 2 goes counter-clockwise.
Equation from mesh 1:
(4+10+1)(i1) - (10)(i2) = 77
Equation from mesh 2:
-(10)(i1) + (2+10+3)(i2)=16
I got the following:
i1 = 10.52
i2 = 8.08
looking at the direction of i1 and i2, I can see that i1 = i_a and that i2= i_c.
I can also see that i_a + i_c = i_b
Therefore,
i_a = 10.52
i_c = 8.08
i_b = 18.6
(all of these are incorrect, the correct answer is i_a = 7.96, i_b = 3.72, and i_c = -4.24)
I am just trying to understand how the problem using mesh analysis. I assume that it would be the same procedure when doing it for the second time with the polarities of the 77V source reversed.