# Questions tagged [kirchhoffs-laws]

Kirchhoff's circuit laws are important for circuit analysis. There are two laws: Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). KCL states that the sum of currents flowing into a node is zero, and KVL states that the directed sum of voltages around a closed loop is zero. Consider also using the "circuit-analysis" with this tag.

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### Electric circuit Characteristic equation from drawing [closed]

Is there a tool that I can draw an electric circuit and it gives me its characteristic equation? Not have to solve it, just give me the equation?
79 views

### How to formulate an equation for the electrical circuit with both a voltage and a current source?

This problem asks me to find Rx, the electrical power of each element and the algebraic sum of the electrical powers of all elements. How to apply Kirchhoff's and Ohm's law correctly in this problem? ...
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### How to calculate current limiter resistor when voltage regulator is involved?

I'm designing my first PCB and I'm not sure if the diagram I found on a datasheet is complete. For what I have read, there should be a resistor between R1 and the transistor Tr1. I have followed this ...
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### How to calculate the value of resistor R2?

How to find the value of R2 in this circuit? If I1 is 8 mA in this case (I = I1 + I2) and then given 5 V over R2 and R3, 5 V/0.008 A = 625 Ω. Is this answer valid ? Or is it 5 V/I = 2mA = 2.5 = 1/2.5 +...
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### What are the currents and the power dissipated by the load $R_{T}$ in the following circuit

The circuit has 2 voltage sources one of which is 0.5UR2, one current source, resistor elements R1 & R2, the load is RT 10 ohms. Having the following circuit, I have used the Kirchhoff's circuit ...
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### How do you use nodal analysis to this circuit?

By using mesh analysis I have 4 equations: 6ia - 2ib = 24 -2ia + 12ib -20ic - 2id = 0 -8ib + 12ic = 0 -2ib + 12ic + 3id = 0 Got ic = 8/3 A, so Vo = 4(8/3) = 32/3 V ; correct me if I'm wrong But I don'...
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### Simplifying a circuit for nodal analysis [closed]

I am trying to simplify/classify the following circuit: My textbook says it is a four-node circuit but I am coming up with 3 nodes. Doesn't the "Ref." dot and the rightmost dot combine into ...
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### Circuit reduction: Voltage across terminals [closed]

I'm new to electrical engineering and there is debate in my class about a problem. We are asked to find the voltage across A and B after reducing the circuit. Circuit is symmetrical. Information given:...
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### How to determine the directions of voltages across resistors in circuit diagrams?

In the following diagram, the directions of both currents and voltages for voltage sources are shown. My task is to write KCL and KVL for all 3 loops, and my question concerns KVL. I believe I am ...
336 views

### Does current prefer to take a series path over a parallel path?

simulate this circuit – Schematic created using CircuitLab Based on the simulation I have done, current here prefers to take the C1 - R2 path first and once C1 is saturated and cuts off it then ...
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### Is there a sequence of thought I can do to solve complex circuits using only KVL and KCL?

This question took me a good 20-30mins of solving, and this just feels like a long time especially when I take my midterm exam it will only be 2 circuits in 1 hour only, so I need to make sure I find ...
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### How does the current direction affect KVL?

I'm a bit confused about using KVL on circuits. For example, suppose I have this circuit, and we are given the direction of inductors current and capacitors current, and we have to find VA. Using the ...
1 vote
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### Current constant circuit

Did this circuit ok since no resistor on circuit? the voltage for each led is 3V for each led. Did i need to add resistor since 3Vx7=21V. The diode is led driver for 15mA. Btw, I'm designed for ...
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### KCL confusion about currents direction

Sometimes when I use KCL for nodes in a circuit I cannot correctly determine the direction of the currents. My book also says that according to KCL the algebraic sum of currents entering a node is ...
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### KVL/KCL and Thevenin Concept [closed]

I have solved the following question but little bit confused that this solution is correct or not as attached in figure. How can I solve this question by KCL/KVL also if by using Thevinin theorem its ...
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### Applying KVL to a grounded MOSFET circuit

I'm rather confused as to how to how this circuit doesn't violate KVL: The two node voltages on the right side of the loop add to -4.16V, which means the voltages on the left should add to 4.16V, ...
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### Derive a State-Space Model for an Electric Circuit with three Energy Storage Components

I want to model the shown circuit diagram with a state-space model. However, I cant solve it since I obtain four unknown variables while only three of the derived equations are linear independent. ...
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### Why is my expression for current I(2) wrong?

simulate this circuit – Schematic created using CircuitLab Hi! My question is if I(2) is a current that runs from Node 1 to Node 2 then the expression of I(2) as a function of I(A), I(B), R1, R2 ...
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### What is I1, I2, I3 and I4?

simulate this circuit – Schematic created using CircuitLab I have really gotten stuck on this question where I need to calculate I1, I2, I3 and I4. The numbers for the circuit is: V(a)=2 V, V(b)=...
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### How many measurements are needed to determine a black box with four terminals?

I am having a black box with four terminals and just resistors inside. I can model it like this: simulate this circuit – Schematic created using CircuitLab If I have four different currents and ...
1 vote
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### Transient Charge Density in Conductor

Veritasium's (Derek Muller's) video How Electricity Actually Works makes the claim at 4:44 that: The truth is, if you average over a few atoms, you find the charge density everywhere inside a ...
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### Why does the E-Field not change given two parallel capacitors?

I just cannot imagine, why connecting two voltage sources in parallel does not change the E-Field (strenghting it) and thus does not lead to higher voltage. In this case charged plate capacitors are ...
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### KCL in a particular node (problem)

Above is an AC circuit in which terminals A and B are used to connect to a load. I am asked to find the equations for currents coming into and out of nodes 1 and 2 (using KCL). I had no trouble ...
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### Why is clockwise KVL done like this?

My task is to find voltage across the resistor of this circuit where all the 4 components are connected in series with each other. The given information are : V1 (t) = 100 * sin(100 * t) V, R = 100 ...
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