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I know applying kcl but I dont know how to consider the directions of the current.What I do is I make a general current direction for the whole loop,then with the help of that I see the currents entrying the node or leaving it but I usually go wrong with this logic..Here's an example which includes my try an the real directions
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  • \$\begingroup\$ Can someone please help me upload both the pictures.In the edit option I see that everythings fine but when I post it the other picture and my details arent visible.Please edit this question for me. \$\endgroup\$ – user1799 Nov 2 '10 at 11:45
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Question statement is a little hazy, but the general idea is, current entering a node gets a positive sign, current leaving a node gets a negative sign, and the sum of all of them comes to zero.

One way to assign currents is to recognize that current flows around the loops. So for each loop, you name a variable for the current. Then it should be straightforward to enumerate the currents entering and leaving a node.

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It doesn't particularly matter which direction you assign to each loop, it's just your best guess, so long as once you pick it, you keep it.

For instance, on Node A, you have blue arrows i1 + i2 - i3 - i4 = 0. That's fine. If you keep that, then when you solve for what the currents actually are, you may find that i2 comes out negative. Which is okay, it just means that the current is flowing in the opposite direction of what you guessed.

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