Mastering KVL and KCL: Tips and Tricks for Solving Circuit Problems

[mmg0789]

Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks won't be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.

 

[berkeman]

Sometimes solving a circuit by KVL and KCL can be a little difficult. What tips/tricks have you gained from solving such circuits? i know that little tricks won't be as helpful as actually practicing, but they will help nonetheless. for example today i discovered it is not a very good idea to go around a loop with current sources. things like that. if you know any good resources that have this kind of information, that would also be helpful. thanks.

I prefer using the KCL method generally, and just label all the nodes and write the current sum equations for each node. Not sure what would be good tips past that... The KVL method is less intuitive for me, and doesn't feel as "physical" as the KCL method.

 

[mplayer]

Some tips that might help with KCL:
-Make your reference node a node that is connected to as many voltage sources as you can to minimized the number of unknown node voltages.
-Sometimes it might be helpful to outline each node in the circuit (draw a border around the wire of each node). Makes it easier to see and keep track of the number of nodes in a circuit, for me at least.

Some tips that might help with KVL:
-I always label the mesh currents going clockwise. Whichever direction you choose to do it in, it might help to always do it the same way to minimizes potential errors.
-If there is a current source in a loop and its on the outside of that loop (not sharing it with an adjacent loop) then that is the value of that mesh current (one less equation to write).

Tips for both:
-Choose the method that will result in having to solve for the fewest number of unknowns
-If there are dependent source(s), write out the constraint equation(s) first, and sub-in those values in terms of the unknown node-voltages or mesh currents as you write the KCL or KVL.
-I always write out the resulting system of equations in matrix form at the end for clarity (puts all the info in one convenient package)


I hope some of those may help. That's generally the way I personally do it, I'm not saying that this is the best way to do it or anything. Good luck!