Voltage problems & Kirchhoff's rules

In summary, the conversation discussed confusion with using Kirchhoff's rules and the formula V=Q/C to find potential in closed-loop circuits. The speaker initially used V=Q/C and got correct answers, but then encountered problems where the values of V did not add up to 0. Later, they learned that ΣV=0 applies to all closed-loop circuits, but were still unsure about when to use Kirchhoff's rules. Another person assured them that, regardless of the formula used, the sum total of potential changes in closed-loop circuits should always be zero. They suggested posting an example for clarification.
  • #1
smile0401
1
0
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
 
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  • #2
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
 

FAQ: Voltage problems & Kirchhoff's rules

1. What is voltage and how is it measured?

Voltage is the electric potential difference between two points in an electric circuit. It is measured in volts (V) using a voltmeter, which is connected in parallel to the circuit.

2. What are Kirchhoff's rules and how are they used to solve voltage problems?

Kirchhoff's rules, also known as Kirchhoff's laws, are two fundamental principles used to analyze electrical circuits: Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). KCL states that the sum of currents entering a node in a circuit must equal the sum of currents leaving the node. KVL states that the sum of voltage drops in a closed loop in a circuit must equal the sum of voltage sources in that loop. These rules are used to set up and solve equations for unknown voltages and currents in a circuit.

3. What is a voltage drop and how does it affect a circuit?

A voltage drop is the decrease in voltage that occurs across a component in a circuit due to the resistance of that component. This can cause a decrease in the overall voltage in the circuit, which can affect the performance of the circuit. It is important to consider voltage drops when designing circuits to ensure proper functioning.

4. How are voltage problems solved using Kirchhoff's rules?

To solve voltage problems using Kirchhoff's rules, you must first identify all the voltage sources and resistors in the circuit. Then, apply KCL and KVL to set up equations for the unknown voltages and currents. Finally, solve the equations to find the values of the unknown variables.

5. Can Kirchhoff's rules be applied to all types of circuits?

Yes, Kirchhoff's rules can be applied to all types of circuits, including series circuits, parallel circuits, and more complex circuits. As long as the circuit is made up of resistors and voltage sources, the rules can be used to solve for unknown values.

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