# Voltage problems & Kirchhoff's rules

1. Mar 6, 2012

### smile0401

I'm getting confused with the problems that ask you to find potential and when to use the rule that the sum of all the V = 0.
There were a lot of questions in my physics book that ask to find a potential in each capacitors and when i was doing those, i just used V = Q/C instead of Kirchhoff's rules (and the answers were right). In those questions, the values of V didn't add up to 0.
But then later, the book started using that ƩV = 0.... and now the V values actually adds up to 0.... and I'm really confused when Kirchhoff's rules apply....
The book says it applies to all closed-loop circuits. but the ones that asked to find potential with V = Q/C were also closed-loop circuits. mmm....
Can anyone please explain this to me? :O

2. Mar 6, 2012

### pabloenigma

Im sure,and confident,that all closed loop circuits you solved using Q=CV, or any other formula in the word, The sum total of potential changes were ALWAYS Zero.Please post such an example,and people will be happy to clarify