What is Kirchoff's loop: Definition and 19 Discussions

Kirchhoff's circuit laws are two equalities that deal with the current and potential difference (commonly known as voltage) in the lumped element model of electrical circuits. They were first described in 1845 by German physicist Gustav Kirchhoff. This generalized the work of Georg Ohm and preceded the work of James Clerk Maxwell. Widely used in electrical engineering, they are also called Kirchhoff's rules or simply Kirchhoff's laws. These laws can be applied in time and frequency domains and form the basis for network analysis.
Both of Kirchhoff's laws can be understood as corollaries of Maxwell's equations in the low-frequency limit. They are accurate for DC circuits, and for AC circuits at frequencies where the wavelengths of electromagnetic radiation are very large compared to the circuits.

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  1. N

    Solving Kirchoff's Laws: Are My Answers Correct?

    Does anyone know how to do part (a). I labelled the current through R1 I1, I4 through R4, I3 through R3, I2 through R2, and I5 through the 3ohm resistor. I used Kirchoff’s Laws to make the equations I1 + I4 = 8, 2I1 + 32I3 - 14I4 = 30, and I1 + I3 - I4 = 0. I solved these equations by subbing...
  2. J

    Using Kirchoff's Loop Rule to Determine Currents in a Circuit

    Homework Statement Homework Equations Kirchoff's Rule The sum of all V = 0 The Attempt at a Solution [/B] I think I'm having a problem determining the current at r_2 and R_3. I had originally thought the currents at both resistors would be I_3, writing E_2 — r_2 I_3 — R_3 I_3 — I_1 R_1 = 0...
  3. L

    Navigate the Res-Monster Maze: Find R's Current

    Homework Statement Res-monster maze. In Fig. 27-21, all the resistors have a resistance of 4.0 and all the (ideal) batteries have an emf of 4.0 V. What is the current through resistor R? (If you can find the proper loop through this maze, you can answer the question with a few seconds of mental...
  4. P

    Find currents I1 and I2 in a 3-loop, 2-battery circuit

    Homework Statement Find currents I1 and I2 in the following circuit: Homework Equations I know I have to use Kirchoff's loop rule but I am not sure of the current going through the 5 ohm and 8 ohm resistors, is it just I1 and I2 respectively? Also do I incorporate the large loop at the...
  5. N

    Kirchoff's Loop Rule Involving 2 Resistors and a Capacitor

    A 5μF capacitor is connected in parallel with a 2MΩ resistor and the combination is then connected in series with a 1MΩ resistor through a switch to a 12V battery. Find the time taken for the voltage across the capacitor to rise from zero initial value to 2V after the switch is closed.From what...
  6. Toon

    Kirchoff's law help with circuits

    Homework Statement The circuit to the right consists of a battery (V0 = 26.0 V) and five resistors (R1 = 211 Ω, R2 = 682 Ω, R3 = 363 Ω, R4 = 534 Ω, and R5 = 465 Ω). Find the current passing through each of the specified points. The Circuit http://i.imgur.com/4JSIHdG.png all I need to find is Ih...
  7. Yorick Chupka

    Kirchoff's Loop Rule ∑ΔV=0 question

    Here is a portion of the explanation my book gives "Kirchoff's second rule follows the law of conservation of energy. Let's imagine moving a charge around a closed loop of a circuit. When the charge returns to the starting point, the charge-circuit system must have the same total energy as it...
  8. S

    How do Kirchhoff's Rules apply to a circuit with multiple resistors in series?

    Homework Statement [/B] Consider the circuit above. You are given the following measured values: V = 1.5 V R1 = 100 R2 = 100 R3 = 50 R4 = 50 R5 = 50 Homework Equations Kirchhoff's Loop Rule and Junction Rule The Attempt at a Solution I tried setting this up using the junction and loop...
  9. M

    Simple Kirchoff's loop problem

    Homework Statement Find the currents going through each resistor. Homework Equations V=IR The Attempt at a Solution [/B] I have the problem worked out and I can't find any errors in my work. The issue is that my professor has: I1=-.0843 I2=.086 I3=.0017 However my physics professor is...
  10. Avatrin

    Kirchoff's loop rule with multiple voltage sources

    Hi Let's look at this: The issue I am having is that while I know that this is accurate: I just cannot wrap my head around why. I1 is a result of both voltage sources. So, while the equations clearly tell me that the voltage drop across the resistor R1 is I1R1, I cannot wrap my...
  11. S

    Calculate Currents Through Ideal Batteries with Kirchhoff's Loop Rule

    "Use Kirchhoff’s rules to calculate the current through each ideal battery in the figure below. R1=1Ω, R2=2Ω, ε1=2V, ε2=ε3=4V. You should apply Kirchoff’s loop rule to the ε1-R1-R2-ε2-R1 loop, and the ε2-R2-R1-ε3-R1 loops respectively, each time starting from the negative end of the battery...
  12. S

    Kirchoff's Loop Rule: Compute R2 Current

    Homework Statement Compute the current through R2 of the circuit in the figure. Homework Equations kirchoff's loop rule V=IRThe Attempt at a Solution Junction: I1+I2=I3 Alpha loop: V1-I3R3-I5R5=0 I1=(V1-I5R5)/R3=? Beta loop: V2-I8R8-I5R5=0 *without one of the currents provided I am not...
  13. A

    Kirchoff's Loop Rule-Direction of Current?

    Kirchoff's Loop Rule--Direction of Current? I came across this question, and it really confused me-- how does the current decide which direction it goes? The pictures are attatched below. The first picture is of the original questions. It gives two scenarios, and asks you what the value...
  14. O

    RC circuit and kirchoff's loop rule

    http://www.screencast.com/users/trinhn812/folders/Jing/media/de5edaba-e848-47f5-82b9-bd770b216e95 I need help with Question 27 specifically. The correct answer is A, but I don't understand why. I thought it would be B according to Korkoff's Loop rule of the inner left loop, where current...
  15. F

    Kirchoff's Loop Rule as applied to Capacitors?

    Homework Statement How does the loop rule apply to capacitors? I can't find any examples of circuits containing capacitors and resistors where the loop rule is used. I know the loop rule measures potential differences, but I'm not quite sure if that has anything to do with capacitors? All...
  16. K

    Kirchoff's Loop Law: Solving DC Circuit w/5V Power Supply

    The problem: I have one loop of a larger circuit. It has a DC power supply set to 5 V, a 220 Ohm resistor, a junction, a 100 Ohm resistor, a junction, a 470 Ohm resistor, a junction, then it goes back to the power supply. The current through the 220 Ohm resistor is 11.71 mA (0.01171 A)...
  17. O

    Why Does Kirchoff's Loop Rule Apply to AC Circuits Using Complex Numbers?

    I was wondering why Kirchoff's loop rule holds for the complex representations of voltage drops in AC circuits. That is, sum of complex voltage drops = 0. I tried working it out from Kirchoff's rule in DC, but am not sure how to proceed properly.
  18. W

    Solving Kirchoff's Loop Rule: Is My Equation Correct?

    I have a diagram on my website and I also attached it to this message. My question is I am wondering if my equation for this loop rule is correct. I am trying to solve it but I am having a problem about the signs I am getting.. This is my equation for this loop: I_2=I_1+I_3...
  19. G01

    Understand Kirchoff's Loop Law: Voltage & Circuit Elements

    I'm having some trouble understanding Kirchoff's loop law. I understand that it is a statement of conservation of energy, and I understand this. My problem comes when we start talking about circuit elements. If we had a shorted battery, the electrons moving through the circuit would loss...