Hey all, I'm trying to apply the Mesh Current theory to Question 19 on this worksheet: http://www.allaboutcircuits.com/worksheets/dc_sp.html

I keep getting these equations:

24 - 1500Ia - 2200(Ia+Ib) = 0

-2200(Ia + Ib) + 5000Ib = 0

This second equation throws me for a "loop" (haha get it?). I keep getting a HUGE current which can't possibly be right. So what am I doing wrong?

Edit: I solved this problem using the easy way (combining the resistances and getting a total current and then splitting the resistors one by one) and got the right answer but I see this as a nice way to practice Mesh Current theory.

 

Hey all, I'm trying to apply the Mesh Current theory to Question 19 on this worksheet: http://www.allaboutcircuits.com/worksheets/dc_sp.html

I keep getting these equations:

24 - 1500Ia - 2200(Ia+Ib) = 0

-2200(Ia + Ib) + 5000Ib = 0
***-2200(Ia + Ib) - 5000Ib = 0

This second equation throws me for a "loop" (haha get it?). I keep getting a HUGE current which can't possibly be right. So what am I doing wrong?

Edit: I solved this problem using the easy way (combining the resistances and getting a total current and then splitting the resistors one by one) and got the right answer but I see this as a nice way to practice Mesh Current theory.

Have to keep your passive sign convention consistent.

 

Hmm...so the second equation is numerically correct?

Edit: I also solved the problem and got the right answer using the Branch method.