# Kirchhoff's Current Law: Solving for Open Circuit Voltage

• princejan7
In summary, the conversation is about finding the open circuit voltage and discussing the current flow through the voltage source and 16 ohm resistor. It is stated that the equations for this problem were not written in a preferred way and the current through the 16 ohm resistor is determined to be 3A using KCL at the Vth+ node.
princejan7

## Homework Statement

http://postimg.org/image/61e06uo7x/

The question is to find the open circuit voltage

## The Attempt at a Solution

Just wondering why the current flowing through the voltage source was left out for node 1
and the current through the 16 ohm resistor was left out for node 2?

princejan7 said:
Just wondering why the current flowing through the voltage source was left out for node 1

It wasn't left out. That's the (24-V1)/10 term.

and the current through the 16 ohm resistor was left out for node 2?

It wasn't left out either. If the output is open circuit then the current flowing through the 16R is 3A.

Aside: Personally I don't like the way they wrote the equations. KCL basically states that the sum of the currents equals zero so I prefer to write the equations in the form I1+I2+I3=0 rather than I1+I2 = -I3

CWatters said:
It wasn't left out. That's the (24-V1)/10 term.

If the output is open circuit then the current flowing through the 16R is 3A.

can you explain why it is 3A
Doesn't the current source send current to the left so that the 16 resistor gets something less than 3A?

princejan7 said:
can you explain why it is 3A
Doesn't the current source send current to the left so that the 16 resistor gets something less than 3A?

Doesn't all the current coming to the current source need to flow through the 16 Ω resistor?

#### Attachments

• Untitled.png
7.2 KB · Views: 419
princejan7 said:
can you explain why it is 3A
Doesn't the current source send current to the left so that the 16 resistor gets something less than 3A?

No.

Apply KCL at the Vth+ node. 3A leaves the node via the current source so 3A must also enter the node from somewhere or the sum won't be zero. The only place it can come from is through the 16R.

## What is Kirchhoff's Current Law?

Kirchhoff's Current Law, also known as Kirchhoff's First Law, states that the sum of currents entering a junction in a circuit is equal to the sum of currents leaving the junction. This means that the total current flowing into a junction must equal the total current flowing out of the junction.

## How is Kirchhoff's Current Law used to solve for open circuit voltage?

Kirchhoff's Current Law can be used to solve for open circuit voltage by setting up a system of equations using the currents entering and leaving the junction. By solving these equations, the open circuit voltage can be determined.

## Can Kirchhoff's Current Law be applied to all circuits?

Yes, Kirchhoff's Current Law can be applied to all circuits, including simple and complex circuits. It is a fundamental law in circuit analysis and is essential for understanding and analyzing circuit behavior.

## What is the difference between open circuit voltage and closed circuit voltage?

Open circuit voltage refers to the voltage across a component or circuit when there is no current flowing through it. Closed circuit voltage, on the other hand, refers to the voltage across a component or circuit when current is allowed to flow through it.

## What are the limitations of Kirchhoff's Current Law?

Kirchhoff's Current Law assumes that the circuit is in a steady state, meaning that the currents and voltages do not change over time. It also assumes that the circuit is linear, meaning that the components do not have any nonlinear elements. Additionally, it assumes that there are no magnetic or electric fields present in the circuit. These limitations must be taken into consideration when applying Kirchhoff's Current Law.

### Similar threads

• Introductory Physics Homework Help
Replies
3
Views
785
• Introductory Physics Homework Help
Replies
3
Views
758
• Introductory Physics Homework Help
Replies
1
Views
378
• Introductory Physics Homework Help
Replies
42
Views
2K
• Introductory Physics Homework Help
Replies
14
Views
833
• Introductory Physics Homework Help
Replies
4
Views
500
• Introductory Physics Homework Help
Replies
18
Views
2K
• Introductory Physics Homework Help
Replies
4
Views
581
• Introductory Physics Homework Help
Replies
8
Views
447
• Introductory Physics Homework Help
Replies
6
Views
2K