I have read in reputed book for circuit theory "Van Valkenburg" that for mesh loop analysis, move all currents in clockwise or antoclockwise directions in all meshes. Just dont move one current in clockwise and the other in anticlockwise. Just to avoid errors.

That is an accurate method to find currents. Now what I have come to see on several websites that you can move currents in any arbitrary direction and you can even choose any loops.The result will be the same. Only the value of current will come negative if direction taken reversed.

http://www.tina.com/English/tina/course/15mesh/mesh

http://www.circuit-magic.com/mesh_current.htm

Please solve this mystery. Can we choose currents in arbitrary direction and in any loops

 

Rushi, the current direction is arbitrary. But, choosing one direction is less prone to error!

Regards,
Phil Corso

 

It does not make any difference which direction each loop current is
assigned.

But if loops have all in the same direction, you get a set of equations that are easy to check. The loop emf equations are all of the form:

(Sum of loop emfs in current direction) = (Loop current x sum of
all impedances around the loop)
-
Sum of (adjacent loop current - shared impedance)

If you are using matrix methods to solve, the matrix of impedances has
positive terms on the diagonal and negative terms for all others.

If you assign an arbitrary direction to each loop you do not get a pattern that is so basic. It is also tempting to assign currents in a direction that is "obvious" which can lead to all sorts of errors.

Cheers,
Bruce.