Kirchoff's Rules: Solve P28.19 Circuit

  • Thread starter Thread starter clairez93
  • Start date Start date
  • Tags Tags
    Rules
AI Thread Summary
The discussion focuses on solving a circuit problem using Kirchhoff's Rules, specifically applying Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). Participants emphasize starting with KCL equations for the circuit's nodes, suggesting to label unknown currents for clarity. The user is encouraged to express the relationship between the currents, noting that the current entering a node equals the current leaving it. Additionally, there is a prompt to consider voltage drops across resistors to further develop the solution. Overall, the conversation aims to guide the user through the application of Kirchhoff's Rules to determine the currents in the circuit.
clairez93
Messages
113
Reaction score
0

Homework Statement


Determine the current in each branch of the circuit shown in Figure P28.19 (attached)


Homework Equations



Kirchoff's Rules:
\Sigma I_{in} = \Sigma I_{out}<br />
\Sigma \Delta V = 0



The Attempt at a Solution



I have no idea where to begin. It's in the Kirchoff's rules section, so I'm assuming those will be used, but how I don't know how to apply them.
 

Attachments

  • IMG_0347.jpg
    IMG_0347.jpg
    16.7 KB · Views: 457
Physics news on Phys.org
Begin at the beginning. Explain what the KCL (1st equation) means, and what the KVL (2nd equation) means.

Then start with the KCL equations for the circuit. Call the bottom node ground, and write the 2 KCL equations for the two top nodes. There are three branches out of the top left node, and two branches out of the top right node... That gives you two equations and two unknowns (the top two node voltages are the unknowns)...

Show us some work, so that we can help you more. That's how it works here on the PF.
 
Oh, and you might try following the "Similar Threads" links at the bottom of the page, in case that helps to get you started writing the equations here in your own thread.
 
… give the unknowns names …

Hi clairez93! :smile:

Hint: start by calling the three unknown currents a b and c (with arrows).

Then write out all the Kirchoff's equations you can think of … what do you get? :smile:
 
Okay, so I have this a current I labeled a going upward along the vertical line at the far right with the 1 ohm resistor in it. Then b and c going downwards along the lines with the 8 ohm resistor and the 5 and 1 ohm resistor line. (b for the 5 & 1 ohm resistor line, and c for the one with 8)

I'm thinking a = b+c according to Kirchoff's first?
 
clairez93 said:
Okay, so I have this a current I labeled a going upward along the vertical line at the far right with the 1 ohm resistor in it. Then b and c going downwards along the lines with the 8 ohm resistor and the 5 and 1 ohm resistor line. (b for the 5 & 1 ohm resistor line, and c for the one with 8)

I'm thinking a = b+c according to Kirchoff's first?

Looks good! :smile:

Now what about the voltage drops across the resistors?

(going to bed now … :zzz:)
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Is This a Series or Parallel Circuit?
Replies
13
Views
895
Using Kirchhoff's Rule - Theory question
Replies
8
Views
2K
Possible confusion regarding application of Kirchoff's Laws?
Replies
2
Views
2K
Solve LC and LRC Circuits Kirchhoff's Rule Problem
Replies
3
Views
2K
Finding the Current in a circuit
Replies
6
Views
3K
Using Kirchoff's Loop Rule to Determine Currents in a Circuit
Replies
2
Views
2K
What are the voltages generated from this current source?
Replies
2
Views
933
Circuit problem involving sources and resistors
Replies
7
Views
2K
Electric Circuit using Kirchoff's rules
Replies
3
Views
1K
Finding potential at a point in capacitor
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top