- #1
PainterGuy
- 940
- 70
Hello, ![Smile :smile: :smile:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Please have a look on the following linked diagram:
http://img32.imageshack.us/img32/1456/img0001vsi.jpg
While applying KVL it is not necessary to have the loop traversing direction and the current direction the same. e.g. the loop could be traversed CW and the current direction could be CCW. But in some situations having the directions for the both current and loop could make things easier such as in mesh analysis. Further, the direction of current defines the polarities of the resistors because the current flows from higher potential toward lower. If a resistor is traversed in the same direction as the current then the IR term would have -ve sign, otherwise it would be +ve.
In the linked diagram if we star traversing the loop from point "a", then the equation would be:
+E - IR1 -IR2 = 0
Question:-
In some cases I have seen when the current enters a voltage source from its positive terminal then the V is +ve otherwise it will be –ve. Why is so? Most often when the current enters the voltage source from its +ve terminal then the V is taken to be -ve. Please help.
Cheers
Please have a look on the following linked diagram:
http://img32.imageshack.us/img32/1456/img0001vsi.jpg
While applying KVL it is not necessary to have the loop traversing direction and the current direction the same. e.g. the loop could be traversed CW and the current direction could be CCW. But in some situations having the directions for the both current and loop could make things easier such as in mesh analysis. Further, the direction of current defines the polarities of the resistors because the current flows from higher potential toward lower. If a resistor is traversed in the same direction as the current then the IR term would have -ve sign, otherwise it would be +ve.
In the linked diagram if we star traversing the loop from point "a", then the equation would be:
+E - IR1 -IR2 = 0
Question:-
In some cases I have seen when the current enters a voltage source from its positive terminal then the V is +ve otherwise it will be –ve. Why is so? Most often when the current enters the voltage source from its +ve terminal then the V is taken to be -ve. Please help.
Cheers